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Crop circles:Rethinking Stand Management

Crop circles:Rethinking Stand Management

Jeffrey S. Ward, Chief ScientistDepartment of Forestry & Horticulture

CT Agricultural Experiment StationNew Haven, CT

Jeffrey S. Ward, Chief ScientistJeffrey S. Ward, Chief ScientistDepartment of Forestry & HorticultureDepartment of Forestry & Horticulture

CT Agricultural Experiment StationCT Agricultural Experiment StationNew Haven, CTNew Haven, CT

Crop circles - OverviewCrop circles - Overview

Crop tree release- Precommercial (tree)- Pole/sawtimber (tree)- Mature sawtimber (tree and stand)

Upper canopy survivalDiameter growthVolume growth

Tying it all together

Crop tree release- Precommercial (tree)- Pole/sawtimber (tree)- Mature sawtimber (tree and stand)

Upper canopy survivalDiameter growthVolume growth

Tying it all together

Crop tree releaseCrop tree release

Figure 2. Side (left) and top (right) views of tree crowns following crop-tree release. Crop-trees are indicated by “C”, cut trees are shown in light grey.

C C

CC

Most value is on few treesMost value is on few trees

Idea – Gary Miller USDA FS NRS

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Precommercial (1988)Precommercial (1988)Sawtimber oak (1995)Sawtimber oak (1995)Mature oak (2003)Mature oak (2003)

Oak crop tree studiesOak crop tree studiesCTCT--DEP, Division of ForestryDEP, Division of Forestry Northeast UtilitiesNortheast UtilitiesMetropolitan District Comm.Metropolitan District Comm. Ferrucci & Walicki, LLCFerrucci & Walicki, LLCTorrington Water CompanyTorrington Water Company Dr. Charles LarkinDr. Charles Larkin

Precommercial crop tree release (CJFR)

Precommercial crop tree release (CJFR)

Tunxis (1988, Oct)Tunxis (1988, Oct)

Initialcrown classDominant 186Codominant 313Intermediate 379Suppressed 372Combined 1250

Initialcrown classDominant 186Codominant 313Intermediate 379Suppressed 372Combined 1250

Oaks may dominate over timeOaks may dominate over time

Few oaks at start

0%

20%

40%

60%

80%

100%

Initial 18-yr later Initial 18-yr laterControl (no release) Crop tree release

Upp

er c

anop

y tr

ees

OtherBeechBirchMapleWhite oaksRed oaks

0%

20%

40%

60%

80%

100%

Initial 18-yr later Initial 18-yr laterControl (no release) Crop tree release

Upp

er c

anop

y tr

ees

OtherBeechBirchMapleWhite oaksRed oaks

Most codominants lost without releaseMost codominants lost without release

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0%

20%

40%

60%

80%

100%

Non

e

Cro

p

Dom Cod Int SupInitial crown class (age 12)

Dis

trib

utio

n at

age

30 Cod

Dom

Crown class at age 30

0%

20%

40%

60%

80%

100%

Non

e

Cro

p

Dom Cod Int SupInitial crown class (age 12)

Dis

trib

utio

n at

age

30 Cod

Dom

Crown class at age 30

1 release long-term benefits1 release long-term benefits

Crown class at canopy closure

None – no crop tree release

Crop – 1 release at canopy closure

Crown class after 18-yrs (30-yr-old)

1 release long-term benefits1 release long-term benefits

0%

20%

40%

60%

80%

100%

Non

e

Cro

p

Non

e

Cro

p

Non

e

Cro

p

Non

e

Cro

p

Dom Cod Int SupInitial crown class (age 12)

Dis

trib

utio

n at

age

30 Cod

Dom

Crown class at age 30

0%

20%

40%

60%

80%

100%

Non

e

Cro

p

Non

e

Cro

p

Non

e

Cro

p

Non

e

Cro

p

Dom Cod Int SupInitial crown class (age 12)

Dis

trib

utio

n at

age

30 Cod

Dom

Crown class at age 30

1 release long-term benefits1 release long-term benefits Oaks may dominate over timebut

You can choose which trees will remain

Oaks may dominate over timebut

You can choose which trees will remain

0%

20%

40%

60%

80%

100%

Initial 18-yr later Initial 18-yr laterControl (no release) Crop tree release

Upp

er c

anop

y tr

ees

OtherBeechBirchMapleWhite oaksRed oaks

0%

20%

40%

60%

80%

100%

Initial 18-yr later Initial 18-yr laterControl (no release) Crop tree release

Upp

er c

anop

y tr

ees

OtherBeechBirchMapleWhite oaksRed oaks

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You can choose which trees will remainYou can choose which trees will remain

Most codominant oaks, including those with good form, will die without release

One (1) release doubles odds Codominants will thrive

Most codominant oaks, including those with good form, will die without release

One (1) release doubles odds Codominants will thrive

XX ??

Increased growth Reduced rotationIncreased growth Reduced rotation

Pole/sawtimber crop tree release Pole/sawtimber crop tree release (CHFC XV)(CHFC XV) Dbh Growth by YearDbh Growth by Year

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Dbh Growth by PeriodDbh Growth by Period Dbh Growth by PeriodDbh Growth by Period

Annual cubic-foot growth (ft3/year/tree)Annual cubic-foot growth (ft3/year/tree) Mature sawtimber crop tree releaseMature sawtimber crop tree release

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Stocking reduced to B-lineStocking reduced to B-line You can teach an old dog new tricksYou can teach an old dog new tricks

Volume growth quickly recoversVolume growth quickly recovers Cutting methods study Cutting methods study (NJAF)(NJAF)

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ShelterwoodShelterwood

Multi-aged crop tree AKACoppice with standards

Multi-aged crop tree AKACoppice with standards

Volume growth maintained (18-years)Volume growth maintained (18-years)

Tying it all togetherTying it all together• Most oaks are lost without management

Crop tree management allows you to select the winners (do not invest in low quality).

• Growth increase is proportional to releaseComplete crop tree release maximizes growth.

• Oaks from 4 to 20+ inches respond

• Best investment is made on codominant stems with grade potential

• Most oaks are lost without managementCrop tree management allows you to select the winners (do not invest in low quality).

• Growth increase is proportional to releaseComplete crop tree release maximizes growth.

• Oaks from 4 to 20+ inches respond

• Best investment is made on codominant stems with grade potential

But there is more!But there is more!

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Rotations periods much shorterRotations periods much shorter Most value is on few treesMost value is on few trees

Idea – Gary Miller USDA FS NRS

SummarySummary• Most economic (and often ecosystem service)

value is concentrated on few trees.

• Crop tree management focuses limited management $$$ on high value trees.

• Stand rotations can be dramatically shortened.

• Therefore – crop tree management can increase stand and regional productivity

• Most economic (and often ecosystem service) value is concentrated on few trees.

• Crop tree management focuses limited management $$$ on high value trees.

• Stand rotations can be dramatically shortened.

• Therefore – crop tree management can increase stand and regional productivity

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Jeffrey S. WardDepartment of Forestry & Horticulture

CT Agricultural Experiment StationNew Haven, CT(203) 974-8495

jeffrey.ward@po.state.ct.us

Jeffrey S. WardJeffrey S. WardDepartment of Forestry & HorticultureDepartment of Forestry & Horticulture

CT Agricultural Experiment StationCT Agricultural Experiment StationNew Haven, CTNew Haven, CT(203) 974-8495

jeffrey.ward@po.state.ct.us