NUS Portfolio of Xiutong Yu

Portfolio of XIUTONG YU Application for admission to Urban Design Program, NUS

XIUTONG YU Bachelor of Landscape Architecture Email: yuxiutong19981213@163.com Phone: +86 13121863155

Contents 01 Coupled Social and Natural Systems

Giant Tortoises as Keys for Solving Ecosystem Degeneration and Colonization Problems in Galapagos Islands Individual Project 2020. 1 - 2020. 11

02 Sustainable Forestry Management Model

"Wood-Wide-Web" Theory Based Model of “Hiis-Plantation” Forest Design in Maardu, Estonia Group Project; Xiutong YU, Ran Zhao, Jiaheng XU 2021. 9 - 2021. 12 Work as group leader, responsible for preliminary investigation, overall logic , "Wood-Wide-Web" research and application. No.3, 4, 5 are independent drawing.

03 Urban Design

Renewal Plan and Landscape Design of Nanhu Districtin in Jiaxing, Zhejiang Province Individual Project 2021. 1 - 2021 6

04 Other Works

Academic 2017-2020

01 Coupled Social and Natural Systems

Giant Tortoises as Keys for Solving Ecosystem Degeneration and Colonization Problems in Galapagos Islands

Who is the invasive species in Galapagos islands?

In my opinion, you humans are the most invasive species of all.

lap

ag

os

tor

toi

se

ch fin in rw Da

Ga

Scalesia

Guava invades

Human first landing

Tourism developing

Human settling

Human and animal interactions make up the island's unique ecosystem, which is the reason why the islands so attractive to visitors.

Fire ant invades

Animals often sneak into farms to eat crops, but they are protected species. Sometimes agriculture does not bring benefits, and abandoned land becomes a greenhouse for invasive plants.

Livestock often compete with tortoises for food.

Imported goods introduce fire ants, which go on a rampage attacking baby animals.

Scalesia, known as Darwin's finches of the botanical kingdom, is the habitat for many animals on the island.

Spread way Competitive relation Predator-prey relationships Guide to the date Certain ecosystems

Invasive species from agriculture and tourism are estroying our ecosystems.

Guava (Psidium guajava L), an invasive specie brought by farmer, is invading entire forest areas. Secretions in their leaves inhibit native plant growth.

Invasive species Native species and human

Birdies and little turtles, are more important for researchers, NGO’s and institutions than local people.

Galapagos Islands: Evolution Laboratory The Galapagos islands were formed by undersea volcanic eruptions four or five million years ago. Due to Peru's cold current, the island's climate is cool and dry, and it is home to many plants and animals unique to the world. 96.6% of the area is now national parks, and only 3.4% is habitat for human beings. On the islands, human beings are only one species of the ecosystem, and we cannot consider urban and nature systems separately. Due to the unique microclimate and elevation variations, the islands form different vegetation and habitats at different elevations.

Conflicts between Galapagos tortoises and tourists Distribution range of Galapagos tortoises Forest Area

Farm Area

Tansitional Area

Migration path of Galapagos tortoises Human route

High-altitude Farm Area: 600-700m

Life and migration are not that comfortable in Galapagos.

Invasive Herbivore’s Competition

Middle-altitude Forest Area: 400-600m

Farm Fence Blocking

Transitional Area：100-300m Eating Promote Invasion

Low-altitude Coastal Area: 0-100m Eat Digest

Compete

Invasive Shrub Blocking

Active seeds Manure

Grow

Human Disturbance

Highway Threat Too thinck!

Invasive Ants’ Attack

Why Giant Tortoises?

Giant tortoises are large herbivores on the island, who often play an important role in ecosystems. At the same time, giant tortoises' travel between highland and beach with high mobility. These factors mean that, tortoises are one of the most important species on the island who have the opportunity to solve the problem caused by human on the island, and to drive the restoration and development of the island. Only by ensuring tortoises’ regular migration, will we be able to maximize their impact on the island's ecology. This is an important part of my design.

HARVEST SEASON

BUSY SEASON

Farmers harvest crops in January and Feburey,while tortoises enjoy sharing the labour.

Some people box the farm with fences, while tortoises can not finish their migration.

We'd like to find ideas to suit them all.

Lifecycle of Galaoagis Tortoises

Food of Galaoagis Tortoises

Migration route of Galaoagis Tortoises

Problems to Galaoagis Tortoises

Browse

Browse

Farmland Area SPRING MIGRATION Tortoises traval back to highland for stable food.

We also find that if seeds of Psidium guajava lay in wetland, they cannot germinate.

Fruit and leaves

Migrate

Migrate

Lichen

Migrate

Tortoises chase nutritious vegetation from highland to lowland. During the journey, they promote the spead of Psidium guajava, a kind of an invasive plant.

Forest Area

AUTUME MIGRATION TOURISM SEASON Tens of thousands of tourist visit Galapagos islands, who greatly disturbe tortoises' mating and breeding. How to release the disturbance is a quite urgent problems.

Browse

Mate

Cactus

Lay Eggs

Human food

INCUBATION PERIOD Fire ant,an invasive animal take the tortoise's Hatch eggs as a kind of food.

Coastal Area

Grow

Hatch

Vegetable

Weed

Low-altitude Coastal Area: Human Territory Problems: Tourists disturb tortoises’ reproduction, invasive fire ants harm baby tortoises.

Measures: Fire ants should be eliminated by eliminating source, guarding against nesting and trapping Design demonstration sections in coastal areas to ensure that people and tortoises do not disturb each other and provide a better viewing experience Demonstration section A

Demonstration section B

Demonstration section C

D Check the container

Lay cedar bark

Poison baits were cast around the nest

Spray diatom powder

A

Cedar bark secrete special esters repelling ants.

With tiny spikes, diatom powder can stab ants to death.

B

Poison baits are spread to the communities by worker ants.

Demonstration section D

C

High-altitude Farmland Zone: Human Territory Problems: 1.Tortoises destroy crops in fields, and humans build fences which keep them from migrating.

2.Farmlands are economically inefficient, and poorly managed farmlands are flooding forests with invasive plants.

Measures: In the farmland area, an ecological corridor was designed by combining the ecological corridor with the farmland, combining the topography with the original migration path of Galapagos giant tortoise.

Travelling the corridor, tortoises will not be affected by farmland fences. In the middle of the ecological corridor, plants that tortoises like to eat (such as cactus) are mainly planted. People can also plant seasonal corps such as soybeans when tortoises are not migrating.

To facilitate management, invasive crops such as guava are planted in the second step of the corridor, which can also distract them from invading the farmland.

In order to improve the income of farmland, banana interplanting with coffee was adopted to improve the benefit, whose wide leaves can block out the intense sunlight and promote the growth of the undergrowth.

Middle-altitude Forest Area: Natural Territory Problem: Invasive species, such as guava invade forest reserves and keep spreading through wildlives like tortoises, which degrads island forest habitats.

Dynamic design

Measures: The giant tortoises seek for puddles and marshes as replenishing points and social centers during migration, where wet soil makes it difficult for guava seeds to

grow properly. Guava seeds can be centrally destroyed by planning the spatial layout of the puddles so that tortoises can bring guava seeds to the wetland.

Considering the spread of guava communities to lower altitudes under global warming, I used cellular automata to simulate the potential suitable habitat and spread trend of guava in the next 30 years, and divided the main communities.

Native trees Ponds now Scalesia Guava Shrub

Before

Guava now

The distance between feeding and excretion of tortoises (400-600m) was used as the radius to determine the dispersal range of seeds.

Guava after 20 years

Ponds after 20 years

Guava after 50 years Pond Seed dispersal range Tortoises' route Pond influence area

Method Combined with the migration direction of tortoises, the location of pond was selected.

A

B

A

C

B

T h e p o n d a r e a wa s s e t according to the area and distance of each pond corresponding to guava community.

C

A

Design When the dispersal of invasive guava seeds by tortoises changes from a positive effect to a negative effect, the dispersal of guava will be greatly limited.

B

A B

C C A A

B

C

B C

After

A.The giant tortoises seek for invasive guava to eat.

B.The giant tortoises finding water on the migration way.

C.The giant tortoises ftransport the seeds of guava to wetland, where they cannot germinate.

Ponds after 50 years

Implications for Natural Vegetation Management Similar to the Australian theory of biological trap for invasive toads, tortoises have inspired me on how to set biological traps for plants. When facing the problem of invasive plants in a large range of natural environment, we can find the "intermediary" who plays an important role in promoting the invasion of plants. It will be an efficient method to find the breakthrough point of plant trap setting on the activity track of the "intermediary".

Meanwhile, giant tortoises, as the island's ecological engineers, contribute greatly to the restoration of native vegetation. In the future, people can also

systematically restore natural vegetation through the spatial layout of attractive elements such as water puddles, with the help of large herbivores such as tortoises.

Tortoises can help restore the Scalesia habitat for other animals on the islands.

Hippomane mancinella

Commelina diffusa

Paspalum conjugatum

Psidium galapageium

Opuntia echios var. gigantea Crotalaria pumila

Tortoise's footprints, a physical way to shapes the vegetation

Some diet composition of Galapagos Tortoise

Zanthoxylum fagara

Tortoises' stomach can increases seeds‘ germination rate by digesting.

Tortoise's faeces, the dispersal agent of many seeds, also speeds up organic recycling and provides fertilizer;

02 Sustainable Forestry Management Model

"Wood-Wide-Web" Theory Based Model of “Hiis-Plantation” Forest Design in Maardu, Estonia

Nature Worship and Forestry Production Continuous Deforestation Isolated Holy Forest of Maardu There is a simple belief in nature among the Estonians, in which ancient forests, trees, and springs are

spiritual, holy trees and holy forests can bring shelter and blessings to the natives; correspondingly, in ecology, ancient trees do play a crucial role in the stability of forest systems. Mature forests transmit information and support each other through a network of roots and fungi known as the "Wood-Wide-Web" (mycorrhizal network) .

With the global advocacy of renewable energy, more and more natural forests in Estonia, a major forestry country, have been developed into plantations, which leads to a series of problems such as the fragmentation of sacred forests and natural forests, the continuous decline of soil potential, and extreme opposition between the people and the forestry sector.

Forest Area

Holy Forest

Cutting Area

Farmland

Forest Reserve

Plantation

Atlantic Ocean

Residence Area Lake and River

This project is based on the nature worship activities and the "Wood-Wide-Web" system. It carries out a comparative study of holy forests (hiis) and artificial forests, and conceived a new type of sustainable forestry management model in the future.

We wish to focus on the following three issues 1. Habitat destruction and natural forest corridor fracture caused by high-intensity forestry production 2. The continuous occupation of Holy Forests(hiis) has resulted in extreme opposition to forestry activities among Estonian residents 3. The soil potential of plantation decreased and presented non-sustainable development

In the Hiis (Holy Forests) In holy forests of Estonia, people hold a series of simple nature worship activities, and they make little impact, like bringing nothing out of “hiis”, because of their respect for them.

Sacred tree, the oldest tree of the whole area, act as the mother of both human and forests, which provide an opportunity for forestry production and spiritual belief to promote each other.

But we cannot igonre the fact that holy forests' borders continue to be deforested, leaving them more fragmented and vulnerable.

Sunlight

Mycorrhizal Fungi Boosting after the Rain

Holy Tree Mother Tree Photosynthesis

Mycorrhizal networks in forests

Rain

Sugar + Cold Air

Vapour

Seeds on Clothes

Vapour

Increased Sunlight Reflection

Seedling

Stamp on the soil

Optimal Rance for Wood-Wide-Web 10m

Maxmum Rance for Wood-Wide-Web

Decomposer

N Mycorrhiza

Soil Microbe

H2O

60m

P

K

H2O

1：17

Plantation

Holy Forest with People

Wood-Wide-Web in Holy Forest

Holy Forest after Rain

Farmland

In the plantations However, in order to ensure timber production, almost all plantations in Estonia are using clear-cut methods and single species, in which it is impossible for the formation of wood dimension net. And this model also has caused frequent disease and insect disasters and reduced soil potential.

At the same time, Estonians are furious that the RMK (National Forest Management Centre) is destroying their forests, so much so that the RMK has had to cut back on harvesting.

Fruit Body （Mushroom）

Resting Spores and Hyphae

1

Spores

Soil Organic Matters

Mycelia Germinating from Hypha (70%)

:

N

40cm

P

Root

In

K

Mycelia Germinating from Spore (30%)

Nutrie

nts

Infromation ts ien

Plant Exudates

Vaccinium Myrtillus, sharing the same mycorrhizal fungi with trees, can provide refuge for the fungi.

H2O

Root

Germination of Mycorrhizal

Hyphal Fusion

tr

Nu

C Root

Destruction of Mycorrhizal

ion

at from

Cu

Few Survive Mycelia (Living in deep soil layer)

100

:

100

Dead Mycelia (Living in shallow soil layer)

100

1

Broken Roots of Tree

:

Vaccinium Myrtillus (a kind of common woody understory plants)

Most ectomycorrhizal fungi can only germinate after being activated by roots, and survive as a symbiont called mycorrhizal; but few can also germinate and grow if soil organic matters present.

Due to the vegetative propagation, hyphae with the same genes can fuse with each other, forming a big net connecting roots of different plants.

Formation of Wood-Wide-Web

Most plantations plant trees of the same specie to maximize benefits, but the woods are prone to pests and diseases.

Foresters clear all the trees by the age of 20, then a new cycle begins.

Before planting trees, foresters remove remaining tree roots, then the soil preparation tractors furrow soil of less than 40cm, killing most of the mycorrhizal. But we also find some interesting things.

The seedlings are very fragile, so foresters need to weed and insecticide for them.

Foresters dig channels to drain water, which can facilitate new growth.

It take a long time for the Wood-Wide-Web to recover, which can not work effectively in the fragile seedling stage, This is a good opportunity to improve forestry.

Soil Preparation

Trees Growing

Clear-cut Logging（20 Years）

Continuous Cover Forestry Model for Plantations

By analyzing the stand volume of Scots Pine, the main timber in the plantation, we found that the production efficiency is highest at the age of 45, and the harvest cycle of Estonian forestry is 30-40 years, which requires us to consider how to make up for the yield gap.

We propose a new continuous cover forestry mode, hoping to increase the rotation cycle to 70 to 80 years, provide a richer age composition and stand composition, and make plantations have an active underground Wood-WideWeb and nature-friendly production mode.

Optimal for Nature

Most Efficient Majority Now

We work out 3 strategies to improve efficiency.

1. Ensure that 70% of the rotation area has more than 5h of sunlight. Adequate sunlight can promote seedling‘s photosynthesis and increase their growth rate.

Lack of adequate sunlight is an important reason why forest managers do not adopt thinning.

22m

L=

36m

L=

28m

L=

Pinus Sylvestris Plantation

Betula Plantation

Picea Abies Plantation

2. Shape the wind adaptation boundaries. With 0.32% of annual forest losses in Estonia coming from storms, shaping buffer zones and harvesting unit blocks along the dominant wind direction helps to form boundaries that minimize wind shear stress. And nomal wind helps naturally spread seeds and fungal spore.

Tall Preserved Conifers Production Tree Trees Short Conifers Shrub

Shrub

Spores and seeds Vaccinium Myrtillus

3

Preserved trees Rotation module The next 3 round of logging area (50 year) The next 2 round of logging area (25 year)

Plantation boundary

The Old-new Border

2

1

Rotation Profile

3. Assist the rapid regeneration of Wood-Wide-Web. Their presence increases seedling survival by 400%, and entire forests are stronger and more resilient to threats because of the alliances they build. Methods like proper irrigation during seedling stage can effectively improve the recovery rate 4 Month 20%

4 Month 35%

4 Month 50%

New Growth Area

Increase Soil Moisture

Keep Refuge Plants

The next 1 round of logging area (25 year) The Wind Rose

P.S: The module in the figure is only to explain one of the effective forms adopted by the principle. In forestry production, it is difficult and does not necessary to strictly follow a certain form or size, but only needs to make a suitable choice according to the strategic principle.

Continuous Cover Forestry Model for Plantations We also provide some suggestions on how to protect and maintain Wood-Wide-Webs during forestry production, and how to use a continuous cover forest.

Pinus sylvestris

Sunlight

Mother Tree Picea abies

The refuge plant in Estonian woodlands, Vaccinium myrtillus, provides both flavorful berries and aromatic ingredients, making it economically valuable.

And mushrooms in the forest are also delicious.

In the artificial forest, which is mainly used for production, we do not add too many manmade landscape elements, but only provide a ground marking system for the mother trees, encouraging people to enter the artificial forest and look for them.

Betula (Birch)

People can hold some outdoor activities at the boundary of different forest production areas, where they can enjoy the sunshine.

People can set up their own devices to harvest the sweet birch juice.

Seedlings

Vaccinium Myrtillus

Logging

Finding and preserving the mother tree and its root system in an area. The mother tree is usually the largest and oldest tree. If their ages are same, select trees that are growing well.

Marking and protecting the mushroom circles, because it marks a dense underground mycelium.

Soil Preparation

Marking the root positions of refuge plants to avoid plowing them when preparing the ground, then they can maintain mycorrhizal communities during the 1 year rest period.

Seeds Sowing

Trees Growing

Leaching seedlings with mycorrhizal soil solution from neighboring forest, which can help mycorrhizal form quickly.

Collecting and sowing seeds from neighboring forest, because mother trees can recognize their children.

It is because of plantation that natural forests are protected from destruction, just embrace sustainable plantations as embrace holy forests.

Atonement and Experiment for Holy Forests

Praying

Meeting

We plan a pilgrimage road for the holy forest. People, as the traditional belief says, do not take away anything from the forests, more do not take direct and cut down a tree to plant trees, just make minor intervention such as unwittingly carrying seeds during nature worship activities. In this way, they will build a corridor landscape connecting the holy forest and plantation in the long years, just like a kind of atonement for human's own actions.

Dancing

Nature Worship Activities Seeds and Spores

Working and Stamping

Swing

Seeds and Spores Putting the sacrifices Beating Clothes

Seeds and Spores

Sustainable Forest Systems The seeds were carried out of the holy land by the pilgrims' shoes and clothing. After hundreds of years, the holy forest will be connected to the continuous cover forest. During that time, they will transport nutrients to each other, improving the stability of the whole forest systems.

Farmland

Plantation Holy Spring

Main Area of Experiment

Holy Forest

2 070

212 0

2 17 0

THE INITIAL SENARIO

EVOLUTION OF FOREST

FINAL FOREST

Holy Spring

Holy Stone Mother Tree Holy Forest

Holy Forest

Holy Forest

New Trees Active Line Farmland

Plantation

Plantation

Plantation

Mature Forest Experiment Site Wood-Wide-Web

Forests of the Future By the time people finish restoring the wilderness between the sacred forest and the plantation, decades, centuries may have passed. But we hope that if Estonian children see this intact forest in the future , which was quickly destroyed and then painstakingly restored by humans, they will have a deeper reflection on Estonian forestry and forest system.

I just want to share a comment I saw on the Estonian forum:

"Maybe our children will learn how to scientifically manage a hundred-year-old forest in a couple of decades, but only if we leave it to them. "

03 Urban Design

Renewal Plan and Landscape Design of Nanhu District in Jiaxing, Zhejiang Province

Who are we designing or planning for?

Due to the site's special historical role, the birthplace of China's governing party, all the planning and design projects of the site, including the current one, are carried out around the solemn, eulogizing, prominent axis, great momentum and stuff like that.

However, this way covers up the temperament and heritage of the site itself as, and ignores the interaction between people and the lake for thousands of years as well as the life and production landscape generated by it.

To make up for this regret, I designed a cultural landscape covering 36 ha at the corner of the site where the city meets the lake.

City-water Form

Activities on the Lake

Big Events

Digging the big canal

I want to design this site as the South Lake cultural landscape. The site is located at the intersection of the city and the lake, consisting of the old town, a classical garden and a deserted wetland .

Using Wei-field irrigation

Urban expansion

Water conservancy projects

Opening the railway

Founding of the govering party

Constructing the highway

Turning into scenic spot

Reshape the Temperament of the Lake I summarized the famous cultural and natural landscapes in the history of Nanhu lake and extracted typical elements for reconstruction, forming five theme areas to rethrive the temperament of the lake.

A

B

C

D

E

A Boat Tour on Old City with New Charm

20 0

Different cultural theme areas will be connected by aquatic tourist line to reshape the water life in the minds of Jiaxing people.

60 40

100 80

Accessible arch bridges Additional terminals Old terminals Additional aquatic tourist line Old aquatic tourist line

Cultural area of different theme

C

D A

E

B

04 Other Works

XIUTONG YU | Portfolio Email: Yuxiutong19981213@163.com Phone: +86 13121863155