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齊來識樹齊來識樹Young ArboristYoung Arborist

1. Introduction to arboriculture and Tree conservations

What is tree?What is tree?

• “Woody plants, having one dominant vertical trunk and a height greater than 5m (15ft).

Are these trees?Are these trees?

Bambusa vulgaris(Common Bamboo 泰山竹)

Common Bamboo Common Bamboo 泰山竹泰山竹

• Monocotyledons 單子葉植物(Liliopsida)

• Family: Poaceae 禾本科

• Absence of dicotyledonous woody xylem

• Vascular bundles scattered throughout the stem• Vascular bundles scattered throughout the stem

Is this a tree?Is this a tree? What is tree?What is tree?

• Angiosperms 被子植物

• Dicotyledons (Magnoliopsida) 雙子葉植物

• Family: Cactaceae 仙人掌科

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Tree classificationTree classification

Spore Tree

Cycads

Ginkgo

Seed Tree

Conifers

Flowering Trees

Primitive Angiosperms

Monocotyledons

Dicotyledons

How trees relate to us?How trees relate to us?• Our Ancestor all lives on trees

Champanzee Urang UtanMacaque

Gorilla

Gibbon

Dusky Langur

©Billy Hau

Benefit of treesBenefit of trees

• Air quality– Air purification

– Carbon uptake and storage

• Air temperature

• Wind block

• Energy saving

• Noise reduction

• Psychological and social benefits

• Economic values

ArboricultureArboriculture

• A branch of horticulture

• Both art and science

• Concerned with – selection of tree

– planting of tree

– care of tree

Three core Three core workscopesworkscopesfor arborists for arborists

Tree selection

• “Match the tree with the site”• Consider its

• aesthetic value, functional value and available stock• characteristics of trees, space for planting trees and its

services

Tree Planting

• Consider • Forms of nursery tree, root form• Soil texture, drainage, depth of planting hole

Maintenance

• Includes pruning, tree diagnosis, plant health care, tree assessment and risk management

Sample of tree selection criteriaSample of tree selection criteria

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Tree plantingTree plantingConsider

• Seeds, liner plants, or cuttings?

• Bare root balled and burlapped (B&B) or containerized?

• Size and quality?

• Season?

• Pruning needed?

• Staking and guying needed?

Tree plantingTree planting

TransplantingTransplanting TransplantingTransplanting

TransplantingTransplanting TransplantingTransplanting

• Side are sloped to allow root growth

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Potential of the tree to fail

Environment Potential target

Tree assessment and Tree assessment and risk managementrisk management

Why assess risk?

• Species

• Growth habits

• Branch attachments

• Defects

• Condition of root system history of tree

• Storms

• Exposure to wind

• Snow 

• Ice

• Loading

• rainfall

• Structure

• Vehicles

• People

• Frequency and intensity of use of the site

Tree assessment and Tree assessment and risk managementrisk management

• Sample of Tree Assessment Form

齊來識樹齊來識樹Young ArboristYoung Arborist

2. Tree management

Tree biologyTree biology

• Vascular system

Source: Arborists’ Certification Study Guide

Tree biologyTree biology

• Defense system of tree

• Compartmentalization OF Decay In Trees (CODIT)

Source: Arborists’ Certification Study Guide

Soil managementSoil management

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Physical properties of soilPhysical properties of soil

50% P

• Ideal Soil composition

5% organic

matter and organisms

Pore space 45%

Mineral material

IrrigationIrrigation

When Where

WhichHow

MulchingMulching

• Organic– Bark– Wood chips– Leaves– Conifer needlesConifer needles– Lawn clippings– Straw

• Inorganic– Crushed Stone– Polyethylene– Fabric

MulchingMulching

• Benefits– Conserve soil moisture– Reduce soil erosion– Increase nutrients– Enhance microorganism activityEnhance microorganism activity– Reduce soil compaction– Moderate soil temperature– Suppress weed growth – And…………

Slow filling of landfills!

PruningPruning Purpose of pruningPurpose of pruning

Reducing risk and inconvenience to public• Keep road clear and safe (Crown lifting)• Free from overhead cables• Remove hanging and deteched branches (Cleaning)

• Maintain road lighting (Crown thinning)

Maintaining health and structure of tree• Remove dead and insect-carrying twig (Crown thinning)• Develop scaffold branches (Formative pruning)• Allow more light and air in or through (Crown thinning)

• Improving appearance (Crown reduction)

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Proper pruningProper pruning Proper pruningProper pruning

Improper pruningImproper pruning Can it survive?Can it survive?

©Philip Yip

No problem~ No problem~ Plant a new one!Plant a new one!

ToppingTopping

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How many problems ?How many problems ? Are they shrubs?Are they shrubs?

Casuarina equisetifoliaCasuarina equisetifolia木麻黃木麻黃

Any Problem?Any Problem?

Any Problem?Any Problem? Any Problem?Any Problem?

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Any Problem?Any Problem? Tree conservationsTree conservations

Are we doing enough?

Champion Trees Champion Trees 冠軍樹冠軍樹 (1994)(1994)

• Encourage effective protection and preservation

• 357 individuals

• Majority dwell in public parks and gardens

Register of Old and Register of Old and Valuable Trees (Valuable Trees (古樹名木冊古樹名木冊) (2005) ) (2005)

• Government policy to provide priority protection

• More than 500 individuals

• Built-up areas (樓宇密集區)

i l d b h d– include both metro and new town areas

– exclude country parks

Register of Old and Register of Old and Valuable Trees (Valuable Trees (古樹名木冊古樹名木冊) (2005) ) (2005)

a) Tree of large size

b) Tree of precious or rare species

c) Tree of particularly old age

(e.g. over 100 years old)

d) Tree of cultural, historical or memorable significance; and

e) Trees of outstanding form

Tree ConservationsTree Conservations

Case Study

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Lam Lam TsuenTsuen Wishing TreeWishing Tree

• Ficus microcarpa

(Chinese Banyan 細葉榕)

• February 2005

8 t b h d ff• 8-metre branch snapped off

• Injure a 62-year old man and a 4- year old boy

• Compacted soil under the concrete and bricks

Credit: chih0427@flickr

Lam Lam TsuenTsuen Wishing TreeWishing Tree

Lam Lam TsuenTsuen Wishing TreeWishing Tree Leung KingLeung King

• October 2006

• Poor pruning

• Common practice in HK

Credit: The Conservancy Association

Chung Chung NgaNga CourtCourt• Ficus microcarpa

(Chinese Banyan 細葉榕)

King of Champion TreesKing of Champion Trees

Credit: The Conservancy Association

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Useful InformationUseful Information名稱 網址

1 Shigo and Trees, Associates LLC http://www.shigoandtrees.com/

2 香港標本室 http://www.hkherbarium.net/Herbarium/index.html

3 樹木谷 http://www.hktree.com/

4 香港野花網 http://www.producegreen.org.hk/hkwildflower/

5 賞樹日記 http://www.hknature.net/treediary/treeindex.html

6 葉脈網 http://www.leafvein.net/

7 100 種香港稀有及珍貴植物 http://www.hkherbarium.net/Herbarium/html%20text/Rare%20plant_table.htm

8 香港植物及植被 http://www.hkflora.com/

9 大樹之歌 http://www.rthk.org.hk/rthk/tv/treestories/20080715.html#programinfo

10 香港50種常見樹木 http://resources.edb.gov.hk/trees/main_page1.html

書籍 出版社

1 風水林 漁農自然護理署

2 香港稀有及珍貴植物 漁農自然護理署

3 賞樹手記 漁農自然護理署

4 水上森林 漁農自然護理署

5 香港自然圖鑑系列 3- 香港海岸植物 野外動向

6 香港自然圖鑑系列 4- 常見灌木叢植物 野外動向

7 香港自然圖鑑系列 11- 香港有毒植物 野外動向

8 香港植物誌 政府新聞處

9 花蹤處處．１００種香港常見野花 綠田園基金

10 植物導賞圖冊 嘉道理農場暨植物園

11 細說榕樹 天地圖書有限公司

12 樹影花蹤--九龍公園樹木研習徑 天地圖書有限公司

13 香港草藥１０徑遊 李甯漢，鄭金順

ReferencesReferencesC.Y.Jim (1994). Champion Trees in Urban Hong Kong, Urban Council, HKSAR

Leung, C. W., C. W. Wong, et al. (2007). Flora of Hong Kong (Vol 1), Agriculture, Fisheries and Conservation Department, HKSAR

Leung, C. W., C. W. Wong, et al. (2007). Flora of Hong Kong (Vol 2), Agriculture, Fisheries and Conservation Department, HKSAR

Leung, C. W., C. W. Wong, et al. (2007). Flora of Hong Kong (Vol 3), Agriculture, Fisheries and Conservation Department HKSARFisheries and Conservation Department, HKSAR

Lilly, S. J. (2001). Arborists' Certification Study Guide. International Society of Arboriculture, USA

Ridsdale, C., J. White, et al. (2005). Trees, Dorling Kindersley Limited

Shigo, A. L. (1989). Tree Pruning, Shigo and Trees

W.Harris, R., J. Clark, et al. (2004). Arboriculture: integrated management of landscape trees, shrubs and vines, Pearson Education

ReferencesReferencesC.Y.Jim (1994). Champion Trees in Urban Hong Kong, Urban Council, HKSAR

Leung, C. W., C. W. Wong, et al. (2007). Flora of Hong Kong (Vol 1), Agriculture, Fisheries and Conservation Department, HKSAR

Leung, C. W., C. W. Wong, et al. (2007). Flora of Hong Kong (Vol 2), Agriculture, Fisheries and Conservation Department, HKSAR

Leung, C. W., C. W. Wong, et al. (2007). Flora of Hong Kong (Vol 3), Agriculture, Fisheries and Conservation Department HKSARFisheries and Conservation Department, HKSAR

Lilly, S. J. (2001). Arborists' Certification Study Guide. International Society of Arboriculture, USA

Ridsdale, C., J. White, et al. (2005). Trees, Dorling Kindersley Limited

Shigo, A. L. (1989). Tree Pruning, Shigo and Trees

W.Harris, R., J. Clark, et al. (2004). Arboriculture: integrated management of landscape trees, shrubs and vines, Pearson Education

Urban Tree Identification and SelectionUrban Tree Identification and SelectionThe concept of “Matching tree and site”The concept of “Matching tree and site”

Why we need to plant tree? Shading

Greening

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Wind Shelter

Noise Reduction

Stormwater RunoffErosion Control

Habitat for Wildlife

The Right Tree for

The Right Place

Tree Selection               

1. Site considerations2. Tree considerations

1. Site considerations

• Environmental factor

S f• Soil feature

• Planting space constraints

• Suitable environment

Environmental factor• Climate

– Rainfall

– Sunlight

– Winds

– Climate change

• Micro-climate

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Example of Micro-climateInfluenced by Building and Structure

Soil feature

• pH

• Texture

• Bulk density

Planting space constraintsPlanting space constraints Planting space constraintsPlanting space constraints

Suitable environment 2. Tree consideration

• Adaptability

• Disease resistance

• Aesthetics

• Tree form and size

• Special tolerant

• Potential problem

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Adaptability

白千層 (Paper Bark Tree)Melaleuca quinquenervia• Exotic species (from Australia)Exotic species (from Australia)• Nice tree form• Thick layer of bark• Widely cultivated in tropical

Asia• Can be planted in extreme

environment– Reservoir– Degraded hillsides– Roadside

Hkhiker, 2010

Disease resistance

樟 (Camphor tree)

Cinnamomum camphora

• Native species

• Reach up to 30m

• Very common tree in “F Sh i W dl d”“Fung Shui Woodland”

• Impregnated with camphor oil

• Can repel most pest except termite

細葉榕 (Chinese Banyan)

Ficus microcarpa

• Native species

Disease resistance

• Native species

• Not very strong in insects and diseases resistance

• But strong in repairing characteristics

Tree form &

Size

© International Society of Arboriculture, 2009

Plant with specific tolerant

- Salt tolerate species

黄槿Hibiscus tiliaceus

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Plant with specific tolerant

- Salt tolerate species

木麻黄Casuarina equisetifolia

Aesthetics

吊鐘 Enkianthus quinqueflorus 海芒果 Cerbera manghas 黃牛木 Cratoxylum cochinchinense

紅花荷 Rhodoleia championii

黃槐決明 Cassia surattensis 水團花 Adina pilulifera

大苞山茶 Camellia granthamiana大苞山茶 Camellia granthamiana

梭羅樹 Reevesia thyrsoidea

鯽魚膽 Maesa perlarius鯽魚膽 Maesa perlarius

Potential problems

• PestPest

• Toxic

• Messy leaves, flowers or fruits

Infested buds & leaves

Erythrina Gall Wasp

Toxic夾竹桃 (Oleander)

Nerium oleander

• Exotic species (from S. Europe, N. Africa & SW Asia)

• Highly adapted in polluted environment

• Toxin might infiltrate into the soil so need to discard carefully

• Burnt out will release toxic material into the air

Messy leaves, flowers or

fruits樹頭菜 (Spider Tree)

Crateva unilocularis

• Exotic species (Tropical Asia and Australia)

• Deciduous treeDeciduous tree

• All leaves will fall before flowering

• Flowering period between March - July

• Causing messy leaves and flowers problem on the street

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Ideal landscape and street trees

Predictable size and form Strong crown structure

Rapid growth rate Ease to transplanting and establishment

Minimal litter (leaf, fruit) Long‐lived

Resistant to pest and diseaseproblem

Tolerant to different environment

Strong compartmentalization response

Deep‐rooted

Excellent aesthetic features  Non‐invasive

(Harris, Clark & Matheny, 2004

Post-planted caring

Why do we needa planter?

Is it enoughIs it enough

for a “TREE”?for a “TREE”?

Is this still

a “Tree”?

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Why still preserve this?

Match the Tree to the Place

ReferencesDoccola J. et al. (2009). Systemically applied insecticides for treatment of Erythrina Gall Wasp,

Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae). Arboriculture & Urban Forestry 2009. 35(4):173-181

Heu A. Ronald et al. (2008). New Pest Advisory Erythrina Gall Wasp- Quadrastichus erythrinaeKim (Hymenoptera: Eulophidae). State of Hawaii, Deparment of Argiculture

Hong Kong Herbarium & South China Botanical Garden .(2007). Flora of Hong Kong (Vol 1). Agriculture, Fisheries and Conservation Department( AFCD), Hong Kong

Hong Kong Herbarium & South China Botanical Garden .(2008). Flora of Hong Kong (Vol 2).Hong Kong Herbarium & South China Botanical Garden .(2008). Flora of Hong Kong (Vol 2). Agriculture, Fisheries and Conservation Department( AFCD), Hong Kong

Hong Kong Herbarium & South China Botanical Garden .(2009). Flora of Hong Kong (Vol 3). Agriculture, Fisheries and Conservation Department( AFCD), Hong Kong

Lilly J. Sharon. (2001). Arborists’ Certification Study Guide.International Society of Arboriculture. International Society of Arboriculture. USA

Lo K.H. (2007). Evaluation of different application methods of Q-Pest in controlling Erythrinagall wasp infestation in Erythrina variegate. Leisure and Cultural Services Department (Sham Shui Po District); NEK Chemicals Limited, Hong Kong

Harris W. Richard, Clark R. James & Matheny P. Nelda (2004). Arboriculture Integrated Management of Landscape Trees, Shrubs, and Vines. Upper Saddle River, New Jersey