MIKKEL JESSEN
VERONIKA MUNGENAST
JULIE KELLER
NELLA ARCE
CARSTEN OLANDER
Exercise 3: Development plan for Jægersborg Hegn
URBAN
WOODLAND
DESIGN
AND
MANAGEMENT
2
Exercise 3: Development plan for JĂŚgersborg Hegn
tABLE OF CONTENT
Introduction Site Analyses Landscape elements and landmarks Woodland stands Infrastructure Soil conditions and protected areas Drainage Design setoff Goals and aims Individual stands Closed drainage system Design proposal Forest development types Grazing forest Beech forest Meadow Waterlogged and moist areas Coppice forest Historical monuments and prehistoric sites Forestry Infrastructure Edges and spatial character Conclusion References
4 5 5 5 6 7 9 11 12 12 12 13 14 14 15 20 22 23 27 27 27 28 29 31 32
Exercise 3: Development plan for JĂŚgersborg Hegn
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Introduction Site In this exercise a development plan for the northern part of Jægersborg Hegn is proposed. Based on analysis of recreation and environmental problems and potentials the plan is developed by balancing the ecological and recreational functions of the woodland.
Jægersborg Hegn
storms, infestations, climate change and increase the biodiversity of the forest. A productive forest is not very interesting from a recreational point of view. The forest is divided up into compartments and stands, with all the different stands having different age classes. The attributes that comes with close-to-nature management will be much more attractive for recreational users and will provide more variation and experiences in the forest.
COPENHAGEN Jægersborg Hegn
Jægersborg Hegn is a forest of 550 hectares owned by the Danish Forestry and Nature Agency. It borders Jægersborg Deergarden to the south. Compared to Deergarden, which is reserved for biodiversity and recreation, Jægersborg Hegn is a productive forest. The Danish Forestry and Nature Agency are in the process of changing all their forest “close to nature” management to more recreational puposes. The principles of ”close to nature” forest management includes continues forest cover, self-seeding, greater use of native species, mixed forest with several different ages in one stand, more old trees and more dead woody debris, protection of key habitats, fewer drainage and the recreation of old wetlands. This change in management will make the forest more resistant to
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Exercise 3: Development plan for Jægersborg Hegn
Landscape Elements and landmarks To the west, east and north of Jægersborg Hegn there is residential areas, and the forest is being used recreationally. A central point in the forest is Bøllemosen, a raised bog with birch stands. There are several ditches around Bøllemosen which have drained the area and led the water into the lake. In addition, there are a number of other ditches in the forest which have drained the soils, and made them more uniform.
There are relatively few open areas and there is a lack of openings or gaps in the forest. The path system in the forest is made up of several straight forest roads, with a number of smaller paths. There is a railroad that goes through the forest and divides up the ”dog forest” and the rest of the forest. In the “dog forest” dogs are allowed to run free.
Bøllemosen
Field Coast/Beach Agriculture Forest Bog Sea Lake City area Railroad Jægersborg hegn Landmark
North Landscape elements and Landmarks of Jægersborg hegn
Exercise 3: Development plan for Jægersborg Hegn
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Analysis Woodland stands JĂŚgersborg Hegn is dominated by broadleaves, and the majority is beech forest, while to the north of the woodland there are a number of oak stands. The rest of the woodland is interspersed with norway spruce stands, douglas fir stands and larch stands. Many of the conifer stands are not integrated well in the landscape.
The stands are many even-aged mono cultures divided into geometrically shaped units, typically for production forest. This gives an unnaturally impression with little aesthetic and recreational quality. Even though a major part of the forest contains beech trees ,the forest lacks coherence due to the rational shaping of the forest and the production-like character of the individual stands.
North
Acer pseudoplatanus Betula Fraxinus excelsior Abies Pseudotsuga menziesii Fagus sylvatica Quercus Larix Lake/water
500m woodland stands
6
Bog Grassland Public area
Exercise 3: Development plan for JĂŚgersborg Hegn
Analysis Infrastructure Path system
The path system is made up of several straight forest roads, with a number of smaller paths. In addition, there is a riding path that goes through the forest. There is also a railroad that seperates the “dog forest” from the rest of the forest.
map showing the path system in relation to the different stands North Rundeforbivej Skodsborg Strandvej
NÆRUM
S
S
Skodsborg station Entering points
SKODSBORG
Intersection points Rail road
Skodsborgvej
Forest roads Path 500m
Stand boundary
The major forest roads are designed to be used in forestry; to transport machines and timber. They usually divide up the stands in a very rigid way. Using these forest roads for recreation means that you usually walk on the edge of a forest stand, rather than in the middle of a stand. There are not many opportunities for different nature experiences along the forest roads. There are three different entering points to Jægersborg Hegn; by the station, close to Nærum and in the north east corner of the forest. mAJOR FOREST ROADS
Exercise 3: Development plan for Jægersborg Hegn
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Analysis Infrastructure The path system has not been designed in a way that is very dynamic with the topography. Some of the smaller forest paths follow the topography a little bit, but not to a great extent.
map showing the path system in relation to the topography North Rundeforbivej Skodsborg Strandvej
NÆRUM
S
S
Skodsborg station Entering points
SKODSBORG
Intersection points Rail road Forest roads
Skodsborgvej
Path Contour curve Contour curve
500m
the Bog
8
Recreation
Jægersborg Hegn is often used recreationally, due to the close proximity to residential areas, schools and kindergardens. There are forest roads in good condition which makes the forest accessible to less mobile users, and there are traditional smaller forest paths, for those who wants to explore less busy areas. There is also a riding path that goes through the forest, and continues in the southern part of Jægersborg Hegn. There are two open public areas in the forest, and there are four areas dedicated to camp fires. As well, there is an area dedicated to tent camping. There is no boardwalk leading through the bog, which excludes some visitors from experiencing the nature connected to the bog.
Exercise 3: Development plan for Jægersborg Hegn
Analysis Soil conditions and protected areas SOIL conditions
The majority of the soils in Jægersborg Hegn is moraine clay that are nutrient rich and well drained. There are also areas with freshwater clay, freshwater organic silt and freshwater peat. These areas have been drained, and the soils are therefore drier. Lake/water Gravel
North
Freshwatersilt
Soil map
Peat
• Luzulo-Fagetum beech forests • Sub-Atlantic Oak-hornbeam forest on damp soils with a high watertable. These types of nature is what makes Bøllemosen a protected area, however, all of these nature types are threatened by a change in the water-table and increased nutrition from the air. Bøllemosen was originally a raised bog, but due to peat extraction it has become a nutrient-poor pond that is affected by ground water. HISTORICAL MONUMENTS
±
There are a number of burial mounds in Jægersborg Hegn and they are all protected according to the Consolidated Act No. 1505 of 14 December 2006 on Mu500 Meter seums. At the northern edge of the forest there is a stone berm, which is also protected by the same law. These historical monuments are also protected by Danish Nature Protection Act §18.
Jægersborg hegn, 2008 GEUS Jordartskort 1:25.000 (c) GEUS og KMS
Freshwaterclay Moraine clay
OTHER PROTECTED AREAS
The field north of the forest is protected according to the Danish Nature Protection Act §33-51.
Protected historical element Betula
North
Bog Protected water
500m
protected areas
Protected bog
NATURA 2000
Protected area
Bøllemosen is a Flora Fauna Habitat protected under the European Natura 2000 network. These areas should be protected because they are in danger of disappearing, they are naturally limited in nature, or the area is characteristic for certain places in Europe. In Bøllemosen there are a number of different nature types present: • Natural dystrophic lakes and ponds. This includes the lake in Bøllemosen which is very humus rich. The lake itself has been created due to the peat extraction which took place up until the First World War. • Transition mires and quaking bogs. Characteristics for these types of bogs are the minerotrophic vegetation in addition to the typical raised bog. The quaking bog is vulnerable to invading species and vegetation, such as beech and sycamore maple. The bog itself is also vulnerable to the pressure of visitors. • Bog woodland which is the broadleaf forest on a humid to wet peaty substrate, with a high water table.
Natura 2000
500m
Exercise 3: Development plan for Jægersborg Hegn
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Analysis Drainage Current conditions of the drainage system
North Significantly wet area Bog Lake/water Drainage
500m
There are a number of drainage systems in Jægersborg Hegn which have been designed to make it possible to grow productive forest on a larger area. Part of the drainage system leads down to Bøllemosen, while there is also drainage leading away from Bøllemosen. This has made the bog smaller, and the productive forest larger. The smaller bog in the eastern part of the forest is also being drained which makes the forest more productive forest in that area. In addition, there is also drainage that leads to the sea or to a sewer system underneath the station. The areas that have been drained has different soil qualities that the majority of the forest, however, due to drainage the soils are now more uniform.
10
current condition
Ditch into the lake
Exercise 3: Development plan for Jægersborg Hegn
Analysis
Exercise 3: Development plan for JĂŚgersborg Hegn
11
Design setoff Goals and Aims In the future JĂŚgersborg Hegn will be managed with close-to-nature principles in mind, focusing on diversifying the forest in terms of recreational use, soil qualities, and hence forest development types. The main focuses of the new management and how will affect the forest regarding the species and the forest type, the spatial feeling of the forest in relation to closed and open areas, the path system and the special uses of the forest. The drainange system currently has a large effect on the forest, and closing the ditches will recreate the more natural soil type. This will also be more in tune with close-to-nature management, since the forest will have a chance to naturally diversify. The forest development types in the forest will now be dependent on the soil type and the species best adapted to the specific areas.
Dog forest
North
Field
Oak
Bog
Beech
major elements
Individual stands Three individual stands were measured and recorded, and a management plan was developed for each of the stands. The three stands represent parts of the types of the new forest; oak grazing forest, waterlogged area and the beech forest.
North
individual stands
Stand 1
Pseudotsuga menziesii
Stand 2
Fagus sylvatica
Stand 3
Quercus 500m
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Exercise 3: Development plan for JĂŚgersborg Hegn
DESIGN setoff closed drainage system
North
Significantly wet area Bog Lake/water Drainage
500m
By stopping and closing the drainage systems, the water balance should restore itself, even though it may take years for the hydrological balance to to normal (Price, J.S, Heathwaite, A.L, Baird, A.J, ). Once the hydrological balance has been restored and these areas have returned to their more natural state, the forest will naturally diversify. Beech does not thrive on waterlogged areas, as opposed to ash, alder, birch, hornbeam, lime, and oak. These trees will then get a chance to grow in these areas without the competition from beech. Closing off the drainage leading to Bøllemosen will not make a significant difference to the waterlevel of the bog, since the surface water will find its way to the
after closing drains
bog through perculation anyway. However the nutrient supply will propably decrease, due to uptake of nutrients from the trees. The drainage leading away from Bøllemosen will have the largest effect on the area. Closing these drains will make the water table rise at least one meter. The surface area of the bog will increase 2-3 times, especially the large flatter areas to the west of the bog. These areas will become significant wetter, and the character of the forest will change dramatically (Hans Kolling).
Exercise 3: Development plan for JĂŚgersborg Hegn
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Design proposal Forest Development Types The overall design for JĂŚgerborg Hegn will include a grazing forest, beech forest, birch forest, coppice forest, bogs, the dog forest and open meadows.
Future design
JĂŚger geus 1:25.00 (c) ge
11
North
92 41 92
11 41
92
11
92
41 13
93
41
11
93
11
41
93 11
11
500m
92
Beech dominated grazing forest
92
Oak dominated grazing forest
92
Grazing forest with alder, birch and ash
41
Birch forest
13
Larch forest
11
Beech forest
93
Forest meadow Bog Protected burial mound
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Exercise 3: Development plan for JĂŚgersborg Hegn
DESIGN PROPOSAL Grazing forest The oak and beech forest in the northern part of Jægerborg Hegn will be developed into a grazing forest. The Norway spruce, abies and the larch stands will be harvested and clear-cut once they are mature, and these stands will then be developed into an oak forest. The north eastern part of the grazing forest consists of relatively young beech stands. When this forest has been heavily thinned out, it should be included in the grazing forest. This will give the beech trees a chance to develop wider crowns, compared to in a beech pillar hall. It would be ideal if the field north of the forest which belongs to Agershvile would be bought or rented to be included in the forest. The grazing forest could then extend out to this open area. The addition of the Agershvile meadow would also break up the sharp edges of the forest, and include some more open areas with interesting topography. The openness of the area also emphasises the topography very well, and provides more variation in the forest.
Grazing forest
Management of grazing forest
The grazing forest is over a large area, which provides the opportunity for moving the grazing animals to another area of the forest. This gives the recently grazed area an opportunity to regenerate itself, so that the future of the forest is assured. Once enough regeneration is present, individual trees or groups of trees can be fenced in and the area can again be used for grazing. The whole grazing forest should not be fenced in at the same time, since this would create a barrier for the users of the forest and the fence would only last about 10 years. Only the areas being grazed at the time should be fenced in. It is also important to be make sure that the field north of the forest only contains 5-10% of the fenced in area.This is to make sure that the animals mainly graze in the forest so the desired grazing forest is achieved (Buttenschøn, R.M). The areas being grazed at the time should still be accessible for the users of the forest, so there should be gates in the fences. The grazing forest should contain a mixture of animals, since the grazing pressure is different for each species. In addition, it would provide more variation and be more interesting for the users of the forest. Consideration needs to be taken when choosing which animals to have in the grazing forest. The aim is to animals whose grazing pressure will provide a species rich flora, while at the same time be user friendly. Goats and sheep are user friendly; however, they have a hard grazing pressure, and hence promote a species poor flora dominated by grasses. Horses and cattle will promote species and herb rich vegetation. Since it will still be possible to enter the area where the animals are grazing, bulls should be avoided (Buttenschøn, R.M).
Exercise 3: Development plan for Jægersborg Hegn
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Design proposal Timeline of the grazing forest
The following deals with the complexities of turning a closed forest of unevenaged stands into an grazing forest. Conversion: 2009
Conversion: 2025-2035
2009 In 2009 there are two larch stands from 1923 and an oak stand from 1837 which is ready to be harvested. Oak and beech trees will be planted in smaller groups in the field to the north of the forest. The larch stand should be clear-cut and oak trees would be planted in smaller groups with 10 - 15 units. The trees should be fenced so the grazing animals can not reach them. When the trees are at the age of 50 the fencing should be removed. Harvesting would take place in the oak stand, however, a number of oak trees should be left to form the grazing forest. The distance between the oaks would be roughly 30-40 meters. This will provide enough light to create a herb layer for the grazing animals. Before putting the animals in, the area should be properly fenced.
2025 – 2035 At this stage, there are conifer stands from 1972 and 1975 ready to be clear-cut. Oaks should be planted in groups and fenced. The fencing can be removed after about 50 years. Conversion: 2049-2062
2049 – 2062 An oak stand from 1921, a douglas fir stand from 1999 and Norway spruce from 1965 is ready to be harvested. The conifer stands will be clear-cut and planted with groups of oak. The oak stand will be harvested, with a number of trees left to form the grazing forest.
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Exercise 3: Development plan for JĂŚgersborg Hegn
DESIGN PROPOSAL
Conversion: 2074-2081
Conversion: 2111-2114
2074 – 2081 There is both beech and oak stands that are ready to be harvested at this time. There is a beech stand from 1956 in the middle of the oak grazing which should be clear-cut, and planted with oak. The rest of the areas will be harvested as mentioned before, with leaving some individual trees.
2111 – 2114 The oaks four oak stands in the final stage of the conversion. The youngest stands from 1973 have now reached harvesting age. They will be harvested and a number of trees will be left in the stand. The two other oak stands from 1983 and 1986 are in middle of the beech forest, so they will be clearcut and planted with groups of beech.
Conversion: 2089-2107
The area of the grazing forest increased from 4,72 hectares in 2009, to 55 hectares in 2114.
2089 – 2107 At this time several stands are ready to be harvested, both of oak and beech. As with the other stands, several trees would be left in the stand to create the grazing forest.
Exercise 3: Development plan for Jægersborg Hegn
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Design proposal
Description of stand 1
The first stand is a Douglas fir stand with Norway spruce from 1999 which is about 3 hectares in size. There are a number of older large larch trees present in the stand as well. The stand consists of one row of Douglas fir, then three rows of Norway spruce, and then another row of Douglas fir, with a distance of 1 meter between the planted trees and 1,5 meters between the rows. The Douglas fir has an average height of 8 meters, while the Norway spruce has an average height of 7 meters. The larch trees has an 30 average height of 30 meters. The soils in the stand is moraine clay, which is the dominating soil in the forest. This soil is nutrient rich and well drained.
20 m
Today (10 years)
Opportunities for the stand
The stand could be clear-cut straight away to make it into an oak grazing forest as soon as possible. This however, will not provide any economic output from the stand. Another possibility would be to develop the stand into forest development type 61; Douglas fir with Norway spruce and beech. This however, would not be ideal with regard to the grazing forest, since conifers provide too much shade for a grazing forest. The third option would be to manage the stand until it is ready to be harvested, so there is an economic benefit from the stand. It would then be developed into an oak grazing forest. Long-term goal
The long-term goal for the stand is to turn it into an oak grazing forest, and hence the third option would be the most logical to choose for this stand. Management Plan
10 m
Norway spruce
Douglas fir
Norway spruce
Measured area 30
+ 90 years (40 years after clearcut)
The Douglas firs will be ready for harvest in about 50 years, while the Norway spruce will be ready for harvest in about 60 years. The stand should be thinned out in the Norway spruce in about 10 years, and from then on the stand should be thinned every second year until the stand is 40 years old. Until harvest, the stand should now be thinned every third year. The Norway Spruce and the Douglas fir should be harvested at the same time. Once the area has been clear-cut it can be developed into an oak grazing forest. The area will be planted with oaks in smaller groups randomly spread out. It will be necessary to fence in the individual trees or groups to make sure they are not being eaten or damaged by the grazing animals. This stand can then be included in the grazing forest.
20 m
10 m
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Exercise 3: Development plan for JĂŚgersborg Hegn
Measured area
30
DESIGN PROPOSAL
30
20 m
+ 90 years (40 + 90years yearsafter clearcut)
20 m
(40 years after clearcut)
10 m 10 m
OaksOaks
OaksOaks Measured area Measured area
+ 200 years
30
+ 200 years
30
20 m 20 m
10 m 10 m
Oak Oak
Ash Ash
Oak Oak
Measured area Measured area
Exercise 3: Development plan for JĂŚgersborg Hegn
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Design proposal Beech Forest The remaining of the beech forest is interspersed with stands of oak, grand fir, Norway spruce, Douglas fir, larch, and ash. When these stands are mature, they will be harvested. Depending on their location, they would either be developed into a meadow, or a beech stand. In the open areas that have just been harvested, pioneer species such as birch and ash will invade the area,and then the beech will take over. The beech forest will have forest development type 11, which consists mainly of beech, with a mixture of ash, sycamore, cherry and oak. Management of the beech forest
The management of the beech forest will be done using group selection, and the areas will naturally regenerate. Parts of the forest will be developed into a beech pillar hall, since this is highly valued among recreational users of the forest. Other areas will be more naturally developed, and have a multilayerd vertical structure. The dog forest in the eastern part of the forest will get a “pillar hall” characteristic. Since it is allowed for the dogs to run free, the dog owner has a better overview and orientation. In addition, the pillar hall in connection with the sea is a very popular forest expression. In the northern part, the forest changes from being a more open grazing forest into a beech forest with “pillar hall” characteristics and then into a dense multi layer beech forest. The southern part of the beech forest will have a more multilayered structure.
Description of stand 2
The beech stand is from 1977, and is 4 hectares in size. Along with beech there was also ash and cherry plum present in the stand. The average height of the trees range from 3,5m to 31,5m, with the average height of the beeches planted in 1977 being 19 meters. There are about 750 trees per hectare in the stand, but according to the age of the stand, there should be about 1500 trees per hectare. There are a number of older beech trees in the stand, which provided the seed source when the stand was regenerated using the shelter wood system. There is very little understory in the stand. The soil profile showed a well drained soil, with a soil moisture category of 5. The soil is both humus rich and shows a high amount of minerals, which makes the soil moderately rich in nutrients. Both the ash and the beech will thrive on this type of soil. Opportunities of the stand
The stand could be developed into a forest development type 11, which consist mainly of beech with some oak, ash, sycamore or bird cherry. The mixed in species occur mainly in groups and conifers mostly as single trees are seldom present. An understory is often absent. The FDT belongs on medium rich, well drained soils with medium to good water supply. The forest type is often developed in a shelter wood system. In mature stands a pronounced horizontal structure is often developed, making it possible to see underneath the canopy. The structure is also known as the ‘pillar hall’, where the recreational value is highlighted with the views giving good impressions of topography, wild life and forest flora. Another option for the stand could be to develop it into forest development type 12, with beech, ash and maple as the dominating species. Around 40-60% of the forest would be beech, where as ash and maple would constitute 30-50% of the forest. Cherry, hornbeam, oak and lime would make up the last 20%. This forest development type need rich, well drained soils, with a good supply of water. This FDT creates a more varied forest, with several vertical layers and larger variation in species content.
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Exercise 3: Development plan for Jægersborg Hegn
DESIGN PROPOSAL
Long-Term Goal
The long-term goal of this stand would be to develop it into forest development type 11. This stand should be developed into having more vertical layers, as opposed to a pillar hall. The public area bordering this stand would be a more intimate open area, since the forest around it is more dense, compared to the public area north west of the bog bordering the meadow.
Management plan
To develop the stand into a beech forest with a more vertical structure, the stand will have to be thinned regularely, as well as creating larger gaps for regeneration of other species will be necesary. The stand will have to be thinned every four year from above. This means that the larger competing trees should be removed, so there will be enough light for an understory to develop. Thinning should especially take place around the ash to allow for its development. Once the beech is of a size which will bring in a good timber price, group selection should take place. This would allow for pioneering species to regenerate in these areas, creating a more species diverse forest, with several vertical layers.
current condition of stand 1: 30 m
30 m
20 m
20 m
10 m
10 m
0m 10 m
0m
Measured area 0m 10 m
0m
Measured area
stand 1, +70 years + 70 years
30 m + 70 years
30 m
20 m
20 m
10 m
10 m
0m 0m
10 m
Measured area
0m 0m
10 m
Measured area
Exercise 3: Development plan for JĂŚgersborg Hegn
21
Design proposal Meadow West of Bøllemosen and the birch stands, there are two Norway spruce stands, 22q and 22o. There is also a smaller stand of grand fir, 29h close by. All of these three stands are right next to the crossing of three path systems. Once these stands have been clearcut and harvested, the beech stand 29 d will also be clear-cut, potentially leaving some of the larger beech trees. This area will then be developed into an open meadow. The size of the meadow will depend upon when the stands are clear-cut, and the meadow will start with stand 29h and the surrounding beech forest. When stand 22o and q are ready to be harvested, these will be included in the meadow. Having an open meadow in this area will emphasise the meeting point of the path systems, and it will create more diversity in the forest. As well, it will emphasize the topography in the area, with the highest point in the area being just south of stand 29h.
MANAGEMENT OF MEADOW
The meadow will be cut once a year, after 1st of july (Buttenschøn, R.M). This is to make sure that the meadow species have finished spreading their seeds for the next year, and it is more protective to breeding birds (Buttenschøn, R.M). Before the meadow is moved, it is important to walk through it with a dog to make sure no baby animals are hiding. The meadow will be mowed mechanically and the hay will be stored in bails for easy storage and removal. It is important that the hay is removed after mowing, so that the meadow will be as nutrient poor as possible. This is also important considering the close proximity to the bog, which also needs to be nutrient poor. Mowing the meadow mechanically might be the most time saving and easiest option, however, there would be greater ecological benefit doing in manually with a scythe. Part of the meadow could be dedicated to a more ecological way of managing it, and this could be done during special events arranged by the Danish Forest and Nature Agency. This would give people a chance to try out and learn about older ways of nature management, and the meadow would be cut by the visitors. The Danish Nature and Forest Agency could also make arrangements with other organisations having scythe courses, and the participants of the course could learn to use a scythe in Jægerborg Hegn. The hay could then be removed by forest workers. This would save time and money for the Danish Forest and Nature Agency, while at the same time promoting nature based forest management.
Burial mound which will be incorporated in the meadow
There is an ancient burial mound close to the highest elevation, and it will be interesting for the visitors if the burial mound is more pronounced in the landscape.
22 q 1982
22 p 1964
22 o 1966
29 d
22
29 d 1969
29 h 1974
the stands to be clear cut for the meadow
Exercise 3: Development plan for Jægersborg Hegn
DESIGN PROPOSAL waterlogged and moist areas Closing off the drains will change the soil conditions, and beech will not thrive in these new wet areas. Instead, these areas will be more suitable for ash, alder, birch hornbeam, lime and oak. These trees will get a chance to grow in these areas without the competition from beech. The north east area of the forest, the south east area of the forest and the area surrounding Bøllemosen will probably be invaded by ash and birch, due to the number of ash stand in this area, and the birch stands around Bøllemosen. The area around the smaller bog in the west will be invaded by birch from the stands around Bøllemosen, and oak from the surrounding stands. The area of the bog will increase, and the openness of the bog could be facilitated by the removal of birch. However, some birch trees should be left to rot for the benefit of biodiversity. The choice of which trees to leave should be carefully considered to make sure they will not pose a hazard for the users of the forest.
Description of stand 3
The area was an oak stand planted in 1953, with an understory of beech. There was also cherry and norway spruce present. The stand has been thinned out among the oaks on a regular basis, and will soon need a new thinning. The tree density is still high, and hence the oaks are starting to compete. The average height among the oaks was approximately 20 meters and 25cm in DBH, while the beech was on average 8-10 meters and 13 cm in DBH. The tree number per hectare for oak was 300, while the tree number per hectare for the beech was 650. The oaks are currently the dominating tree with a highly elevated crown due to the density of planting with a spacing of an average of 2,5 to 3 meters. The beech is the co-dominating trees with a low crown. It is more or less evenly spread with spacing that varies from 2 to 5 meters. The stand is just north of a drain, which will be closed once the surrounding beech is ready to be harvested.
Management of the waterlogged areas
The management of the waterlogged areas should take place in the winter when the ground is frozen, so the least amount of damage is done to the area. It could potentially be done with horses. The trees will still be felled in groups, and the area will naturally regenerate. The economic potential of the stands in the area of the drains should be taken into consideration before the drains are closed. There are two areas with current drains that are ready to be harvested, so these drains can be closed once the timber has been harvested. The rest of the drains will be closed and stopped once the stand in that area is ready to be harvested.
Exercise 3: Development plan for Jægersborg Hegn
23
Cross section of the current conditions
20 m
20 m
10 m
Oak
Beech
Oak
Beech
Oak
Oak
Beech
Oak
Beech
Oak
Oak
Beech
Oak
Beech
Oak
Beech
Beech
Oak
Oak
1
Design proposal
20 m
10 m
Measured area
Opportunities of the stand
Long-term goal
There are three options of what to do with the stand and how to develop it.
We have chosen the last of the three options as our long-term goal. These species will be better site adapted to the future waterlogged area due to the closing of the drains. Developing the stand into a grazing forest will create a coherent spatial expression which is in tune with the rest of the grazing forest surrounding it. However, before it is developed into a grazing forest, the productive potential of the stand should be realised.
20 m
10 m
Beech
Oak
Beech
Oak
Beech
Hornbeam
Hornbeam Oak
Measured area
Oak
Beech
Oak
Beech
Beech
Oak
Beech
Oak
Hornbeam
Hornbeam
If the stand is being left unmanaged, the oak will continue suppressing itself by intra-specific competition. The crowns will not develop to its full potential. The beech will eventually out-compete the oak and take over the stand, and there will continue to be a beech understory.
10 m
20 m
One option is to develop the stand into good productive oaks, using hornbeam as an understory to shade out the beech.
20 m
Another option is to develop the stand into a grazing forest with alder, ash, birch and oak. 10 m
Oak Beech
Beech
Ash
Ash
Ash
Hornbeam
Oak
Hornbeam
Oak
Beech
Beech
Hornbeam
Oak
Beech
Beech
Hornbeam
Hornbeam
Oak
10 m
Measured area
24
Exercise 3: Development plan for JĂŚgersborg Hegn
DESIGN PROPOSAL
areas, and an understory of hornbeam will be planted instead. The hornbeam will be planted in groups to leave some open areas so the ash has a chance to self seed. The hornbeam will be planted in groups of 6 x 6 meters. The hornbeam will be planted with a density of 2 x 1,5 meter (2 meter between the individuals, and 1,5 meters between the rows), and thinned as often as needed to make sure they develop large crowns and still create a vision of standing in a group. The hornbeam will be planted at an age of 3-4 years, and the groups of hornbeam will therefore have to be fenced to make sure the game does not eat the seedlings. Until the hornbeams are off a size where they will not be outcompeted by the beech, active removal of the beech must take place. The fence will be removed when the hornbeam are too tall for the game to reach. In the areas where hornbeam is not planted, there will still be an understory of beech. Active management needs to take place, so that the beech will not be a competition for the oak.
Management plan
In the management plan we have to consider thinning, planting, and control of the understory.
20 m
20 m
10 m
Oak
Beech
Oak
Beech
Oak
Oak
Beech
Oak
Beech
Oak
Oak
Beech
Oak
Beech
Oak
Beech
Beech
Oak
Oak
The oak needs to be thinned out strongly from below, so the existing healthy ones have room to develop the crown. Currently, the oaks have a high density (300/ha), and are competing intra-specific. The oak stand needs to be thinned on a regular basis, to make sure a more realistic density is achieved for the stand. Thinning will be done on a 4-year basis until the stand is 85 years old, where the thinning will be done on a 5-year basis until the stand is 120 years. From 120 years to 150 years thinning will be done on a 6 year rotation. Thinning will be done both in groups and single trees. More thinning will be done around certain oaks to develop a wider crown. These trees will not be harvested, but will eventually be a part of the grazing forest. The thinning will also be more beneficial for recreation purposes since there will be variation, and the forest will be more open than a beech forest. The understory of beech will be removed in certain
20 m
10 m
Measured area
20 m
x1
10 m
Beech
Oak
Beech
Oak
Beech
Hornbeam
Hornbeam Oak
Oak
Beech
Beech
Oak
Beech
Oak
Beech
Oak
Hornbeam
Hornbeam
Cross section a 100 years after first intervention
10 m
Measured area
20 m
r) 20 m
10 m
Oak Beech
Beech
Ash
Ash
Ash
Hornbeam
Oak
Hornbeam
Oak
Beech
Beech
Hornbeam
Oak
Beech
Beech
Hornbeam
Hornbeam
Oak
10 m
Measured area
Exercise 3: Development plan for JĂŚgersborg Hegn
25
Design proposal
The ash stand north of the area will act as a seed source to spread the ash into the gaps created by thinning. When the oaks are 150 years old, they should be harvested, except for the trees that have been selected for the grazing forest. At this time, the surrounding beech will also be harvested, and the drains can be closed. This will cause the area to be more wet. This will not be good site condition for beech, so other species, like ash, alder and birch will establish in this area together with the few oaks. Before the area is being opened for grazing, thinning should be done in the hornbeams. This is because
the hornbeams shade out the understory herblayer. When opening up for grazing, the young birch, alder and ash will have to fenced in to be protected against the grazing animals.This fencing will be removed once the trees are large enough.
the grazing forest 200 years from establishment of hornbeam
30 m
20 m
10 m
Oak
Ash
Birch
Oak
Hornbeam
10 m
Measured area
26
Exercise 3: Development plan for JĂŚgersborg Hegn
DESIGN PROPOSAL coppice forest
Forestry
The wetter area south east in the forest will develop into a forest development type 91; an alder coppice forest with standard containing ash and birch. The coppice trees will be multi-stemmed and provide fuel wood, while the single trees will provide timber. The coppice forest gives people a chance to see an ancient form of forest management, and there are many opportunities of how the Danish Forest and Nature Agency can include the public. The Danish Forest and Nature Agency already have many open days with different topics, and JĂŚgersborg Hegn could be a good place to show older forms of forest and nature management. In addition, the coppice forest will contribute significantly to the biodiversity of the area, since many redlisted species are found in connection with this FDT. The location of the coppice forest will also provide a new element to the forest. There are three major entrance points to the forest, and each one will start in a different type of forest; either alder coppice forest, oak grazing forest or beech grazing forest. The coppice forest will provide a dense room in the forest, which is continued in the following multi layered beech forest.
The management of the forest will be following the principles of close-to-nature management, and harvesting will be done in group selection with natural regeneration. Extracting of the wood will still be done mechanically, however, some areas which are more sensitive can be done with horses. Harvesting will take place in groups of trees, which have been marked by the forester. They will be cut by the forest workers, and the logs will be dragged out to the skid trail by the horses. The logs are then being picked up by a forwarder on the skid trail. There will be less skid trails in the forest compared to conventional forestry. Having working horses in the forest would be beneficial in a number of ways. First of all, horse-logging will be less damaging for the forest, which will go well with the principals of close-to-nature forestry. It would also be nicer for the visitors to come across horses working compared to larger forest machines. As well, it would be a selling point for the Danish Forest and Nature Agency, and it would attract visitors who want to see a different way of doing forestry. The group selection will make smaller glades around in the forest. Some of these glades will be possible for visitors to find in the forest and hence use, while others would be more hidden in the forest.
Management of the coppice forest
An alder coppice forest will have a rotation age of 2040 years. The coppice forest will consists of several areas with different age classes, however, these areas should be larger than 0,25 hectares in size. This minimum size is necessary so that there is enough light for the roots to resprout. Historical monuments and prehistoric sites Historical monuments and prehistoric sites
The prehistoric sites in the JĂŚgersborg Hegn should be more pronounced in the landscape. There should be maps or signs showing where they are, and notice boards next to the most historically interesting ones. Management of the historical monuments and prehistoric sites
The burial mounds and the stone berm must be kept clear of vegetation such as shrubs. If trees are felled on the burial mounds, the root must not be removed since this could potentially damage the structure and stability of the burial mound.
Horse logging
Exercise 3: Development plan for JĂŚgersborg Hegn
27
Design proposal INFRASTRUCTURE Pathsystem
A boardwalk path system should be created over the bog, so the users still have the possibility to experi ence the area, even though it is wet. It would also be an ecological advantage to have a boardwalk since the bog is a Natura 2000 area. The boardwalk would protect the bog from a high visitor pressure in the area. The boardwalk will connect the northern and southern parts of Bøllemosen. Open areas
The open areas in the forest will increase with this new management plan. The public area in the east of the forest will remain the same, while the other public area north west of the bog will be extended with the creation of the meadow. The grazing forest in the northern part of the forest will give the forest a more open feel, as well as the addition of the field next to Agershvile. The bog will also expand with the closing of the drains, and this will add to the openness of the forest. This will especially be emphasized from the public area in the north west of the forest where there will be a better view of the open bog with the creation of the meadow. Jægersborg hegn, 2008 geus Jordartskort 1:25.000 (c) geus og kms
11
North
500
± Meter
92 41 92
11 41
92
11
92
41 13
93
41
11
93 93
11
92
Grazing forest beech dominated
92
Grazing forest oak dominated
92
Grazing forest with alder, birch and ash
41
Birch forest
13
Larch forest
11
Beech forest
93
Forest meadow
41
Bog 11
11
Lake/water Protected burial mound Forest road 500m
28
Path Boardwalk
Exercise 3: Development plan for Jægersborg Hegn
DESIGN PROPOSAL Edges AND SPATIAL character The grazing forest in the north has a semi-open character. The edges to the northern plain and in the south to the forest meadow are ecoclin 1-step edges. The trees are spreading out into the landscape. Although the grazing forest intertwines with the field, the berm will still be pronounced in the landscape. This is due to the high visibility of the grazing forest, and the distances between the trees. The public area in the eastern end of the forest borders two different beech forests. The public area is enclosed by a 2-step edge on one side and an ecoton 1-step edge on the other side. This leads to a sheltered feeling and a view into the "pillar hall". The multi layer forest has also a 2-step edge to the forest meadow, which gives a closed landscape room and emphasises the meadow with its opened topography. Further along the forest meadow a sharp 1-step
edge leads into another part of the beech pillar hall forest. This gives an open view from inside the pillar hall to the open meadow and into the birch stand and the bog. This part of the beech forest is again an intersection between the more open grazing forest and the dense beech forest in the south.
Existing border to the north
11
North grazing forest
92
ecoclin 1-step edge
41
beech forest with ”pillar hall” character
92
ecoton 1-step edge
A 11 92
41
A’
B
92
2-step edge 11
C
93
beech forest with multi layer character
Birch forest Larch forest
B’ 41 13
C’
41
11
93 93
11
41
11
11
500m
Exercise 3: Development plan for Jægersborg Hegn
29
Design proposal
opening up the forest around the berm
0m
30 m
cross section A
grazing forest, the meadow and the bog
cross section B 0m
30 m
‘Pillar hall’ z
0m
30
30 m
cross section C
Exercise 3: Development plan for Jægersborg Hegn
Dispensations
Conclusion
It will be necesary to apply for dispensations from the nature protection and Natura 2000 restrictions in relation to adding Agershvile field and to the possible future changes in Bøllemosen.
This development plan for Jægersborg Hegn will provide the recreational users of the forest with a more varied and natural experience. They will have a chance to experience both different types of forest, and older forms of nature management which is more beneficial for the ecology of the forest. The forest will be dominated by a beech forest, both with the highly valued pillar hall, and areas that are more natural with several vertical layers and less visibility. The forest will be more open than it is now, since a meadow will be created and a large part of the forest will be grazing forest. There will also be rooms in the forest that are very dense at times, like the coppice forest in the south east corner of the forest. The older forms of management, like grazing, coppicing, and horselogging, will be very beneficial for the biodiversity of the forest. There are many red listed species in the coppice forest. and the meadow and grazing forest will add new species to the forest. The increase in biodiversity will make the forest more resilient towards pest attacks, climate change and storms. It can be expected that the residents of Skodsborg, Nærum and the northern residential areas will use Jægersborg Hegn more and it will turn into a meeting area. The development of Jægersborg Hegn as a closeto-nature forest management with more recreational value works an extension of Deergarden as a highly valued recreational area for greater Copenhagen.
Exercise 3: Development plan for Jægersborg Hegn
31
References Price, J.S, Heathwaite, A.L, Baird, A.J, Hydrological processes in abandoned and restored peatlands: An overview of management approaches, Wetlands Ecology and Management, 11, 2003, pp. 65-83 Hans Kolling, Skovfoged, Skov og Naturstyrelsen, email 08.01.09 Federal Agency for Nature Conservation, http://www.bfn.de/0316_typ9110+M5054de7a952.html Buttenschøn, R.M. (2007): Græsning og høslæt i naturplejen. Miljøministeriet, Skov- og Naturstyrelsen og Center for Skov, Landskab og Planlægning, Københavns Universitet, Hørsholm, 2007. 250 s. ill., p. 38 Larsen, B.J, Rasmussen, K.R, Callesen, I, Ecology of tree species and species selection, Larsen, J. Bo et al. The long-term goals for nature-based forestry - The forest development type. Miljøministeriet
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Exercise 3: Development plan for Jægersborg Hegn
33 Exercise 3: Development plan for JĂŚgersborg Hegn 6/8