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Growing High Quality Trees

Crop tree selection and

treemarking

Minga O’Brien, MSc, Forest Tech

October 2, 2010

Crop tree selection

• managing individual trees to grow high quality

sawlogs

Hemlock logsWhite pine logs

What are crop trees?• Better quality trees in a stand

• To be harvested later

• Straightness, vigour, lack of limbs & defects, $value

Red oakWhite

ash

Red

spruce

More crop trees species

White pine Yellow birch Eastern hemlock

Ideal crop tree:

• Dominant or co-dominant crown position

Ideal crop tree:

• Good-sized crown

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Ideal crop tree:• Well-balanced crown

• Straight, branch-free bole

Ideal crop tree:

• Crown has lots of fine branching

• Dead branches, thinning needles not good

Low High

White ash

Red oak

Ideal crop tree:

Bark:

• Smooth

• Light-coloured

• Shallow furrows

• Tight, not flaky

Vigorous yellow birch: shiny, light-coloured

Low High

Assessing risk

• Is tree going to die

before next cutting

cycle?

• Are the risks major

or minor?

Assessing riskLow risk = Acceptable Growing Stock

High risk = Unacceptable Growing Stock

UGS trees have decay, damage or structural defects

Target canker Spiny tooth fungus

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Interior decay - major defect

Large dark face scarBlack bark

Butt flare

Moderate to major defects

Spiral seam

Black knot

Lean

Structural defects

Weevil damage

on white pine

Sweep V-shaped fork

Can the tree respond to more light?

Tree species that increase in growth with more

light:

•Sugar maple, hemlock, white ash, red oak, red

spruce, white spruce

Tree species that respond well to more light when

young:

•Yellow birch, white pine

How to manage for crop trees?

• Thinning treatment to release crowns of chosen

crop trees by removing less desirable trees

• Promote growth & quality development of your

best, highest potential trees

Select Crop Trees Identify Competing Trees Remove Competing Trees

Spacing is important!

• Ensure adequate growing space for crown & root

development of crop trees

• A healthy crown grows outward each year - up to 1

foot per year

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Be patient!• Do not remove all UGS in one entry

• Gradual release of crop tree crowns

• Important to maintain canopy cover

Shade tolerance

• Shade reduces direct sunlight, maintains

moisture, protects against weather

• Some species grow under shaded

conditions, others do not

• Smaller openings encourage hemlock,

sugar maple, red spruce

Red spruce, hemlock, white pine

& red oak regeneration under

partial tree canopy

Treemarking

• Marking of trees for harvest, or for retention

• Key step towards growing high quality logs

• Careful selection of trees based on tree size,

vigour, quality, biodiversity

and wildlife values

Why mark trees?• Small investment with good return

• Sawlogs prices of some species have steadily increased

• Well managed woodlot can increase growth of crop

trees

How can it help?

• Increases familiarity with woodlot

• Facilitates planning for access,

felling and extraction

• Cutting and harvesting

operations more efficient

• Allows woodlot owner to

visualize the harvest and

influence choices

Is treemarking different from

crop tree selection?

Treemarkers have to take

into account many

factors:

tree vigour and defects,

shade tolerance,

site conditions,

wildlife habitat,

forest biodiversity.

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Costs

• Costs vary with terrain, size of area to be

marked, boundary lines, access,

treemarking paint, and travel distance

• The cost may be covered by funds made

available through the Forest Sustainability

Regulations

Treemarking 101

#1. Cut the worst first.

Remove trees with cankers and fungi

Remove severely damaged trees

Remove poorly formed trees

Remove trees with low vigour

Pre-harvest Post-harvest

#2. Maximise future growth.

Retain healthy well-formed trees

Space AGS trees

Know what species

respond to light

Maintain basal area

Treemarking 101

#3. Retain trees of all sizes.

How many trees are 4”-10” in diameter? 10”-

14”? 14-18”?

Take 1 out of every 3 or 4 trees in every size

class

Treemarking 101

#4. Maintain diversity.

Keep a range of tree species

Do not remove uncommon tree species

Keep conifers in hardwood stands, and

hardwoods in conifer stands

Be careful near wet areas and unusual stands

Treemarking 101#5. Wildlife need a home too.

Keep cavity trees

Keep mast trees

Protect active and inactive stick nests

Treemarking 101

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Be flexible!