2010 Western Mensurationists Meeting Response of crown and canopy structure to stand density regime...

transcript

2010 Western Mensurationists Meeting

Response of crown and canopy structure to stand density regime in western

conifers

Doug Maguire Giustina Professor of Forest Management Director, Center for Intensive Planted-forest SilvicultureCollege of ForestryOregon State University

Topics

Crown and canopy structure of western conifers

Crown structure

Spacing effects on crown structure– Pringle Butte lodgepole-ponderosa pine

mixed species spacing trials– Lookout Mountain ponderosa pine-

grand fir mixed species spacing trials

Other silvicultural influences

Needs and directions

Topics

Crown structureSpacing effects on crown structure– Pringle Butte lodgepole-ponderosa pine

Why crown structure ?

Crown size drives growth and vigor

Crown size and its aggregate as canopy structure is key element in wildlife habitat (structural diversity) Crown area profile

height

Crown area

Crown size influences wood quality (branch size, crown wood core, microanatomy )?

Josza and Middleton 1994

Branch diameter

Crown wood core

Crowns ARE the tree-atmosphere interface (gas and heat exchange, light interception) z

N o rth

Crowns represent potentially utilizable biomass (biofuel feedstock)

Crown structure influences fire behavior

Crown length?

Resolution of crown structure for differing objectives

What level of detail do we need for the purpose at hand?

(Crown ratio)

Crown length and

crown width?

Crown length and crown width and

biomass?

(leaf, branch, . . .)

First-order (primary) branches?

Branches of all orders with detailed spatial information?

Spatial structure of all branches and leaves, or all structural modules?

As with any model, the objective or question dictates the appropriate

level of detail

For given objective and level of detail, does silviculture influence crown structure?

Topics

Crown structure

Spacing effects on crown structure–Pringle Butte lodgepole-ponderosa pine

mixed species spacing trials–Lookout Mountain ponderosa pine-

Pringle Butte and Lookout Mountain mixed species spacing trials

6.5 miles

Lookout Mountain

Pringle Butte

Wickiup Reservoir

Crane Prairie Reservoir

La Pine

Pringle Butte ponderosa pine x lodgepole pine spacing trial

• Five initial spacings: 6, 9, 12, 15, 18 ft• Three species mixes:

• pure PP• pure LP • 50:50 mix PP/LP

• Planted in 1967• PP/bitterbrush/snowbrush/sedge plant association• Site index approximately 60 ft at 50 years• Elevation ~ 4600 ft• Annual precipitation ~24 inches

18 x 18 ft

6 x 6 ft

Lookout Mountain ponderosa pine x grand fir spacing trial

• Three initial spacings: 6, 12, 18 ft• Three species mixes:

• pure PP• pure GF • 50:50 mix PP/GF

• Planted in 1974• Mixed conifer/snowbrush/chinkapin plant association• Site index approximately 90 ft at 50 years• Elevation ~ 5100 ft• Annual precipitation ~39 inches

Lookout Mountain ponderosa pine x grand fir spacing trial

18 x 18 ft

6 x 6 ft

Mixed species spacing trials

Measurement schedule

Pringle Falls

Lookout Mountain

Mixed species spacing trialsGarber and Maguire 2004 Forest Science

Standing volume ~proportional to initial spacing

Periodic annual increment starting to level out across spacings

15-20 yrs

20-25 yrs

25-34 yrs

Interaction of spacing and species composition on relative height development.

Implications for canopy structure, ladder fuels, spatial variation in crown bulk density.

Intensive crown sampling

Sean Garber M.S. Thesis

Meticulous lab analysis of branches

Relative amount of foliage

Shift in relative foliage and branch distribution among different initial spacings influence spatial pattern in crown bulk density

3 6 9 12 15 18 210

Foliage bulk density by spacing

lppureflpmixfpppurefppmixf

Spacing (ft)

3 6 9 12 15 18 210

20Branchwood bulk density by spacing

lppureblpmixbpppurebppmixb

Spacing (ft)

3 6 9 12 15 18 210

30Crown bulk density by spacing

lppureclpmixcpppurecppmixc

Spacing (ft)

)Pringle Butte ponderosa pine x lodgepole pine spacing trial

Spacing effects on crown recession

More rapid recession at closer spacings implies:- Loss of biomass- Accumulation of fuel

Plantation age (years)

0 20 40 60 80 100

ity in

Three initial spacings Three thinning intensities

Moderate

Lookout Mountain

Pringle Butte

Total height

Height to crown base

0 20 40 60 80 100

Total heightby spacing

Height to crown base by spacing

5.53.71.8

1.83.75.5

Ponderosa pine simulations based on initial conditions at Pringle & Lookout

Three initial spacings grown out 100 years:

6-ft12-ft18-ft

Thinning at years 25, 50 and 75, and all grown out 100 years:

Residual SDI(% of max):

55%41%27%

0 20 40 60 80 100

Stand age (years)

0 20 40 60 80 100

25000P

Lookout Mountain Pringle Butte1.8

3.73.7

5.55.5

Ponderosa pine simulations based on initial conditions at Pringle & Lookout

Number of branches

Branch necromass

Branch diameter

Stand age (years)

0 10 20 30 40 50 60 70 80

Annual branch mortality for ponderosa pine under different initial spacings

Spacing effects through:- Time to crown closure- Rate of height growth after closure

0 20 40 60 80 100

1400Lookout Mountain

Pringle Butte

Annual branch mortality for ponderosa pine under different initial spacings

Site quality effect through rate of height growth rate of crown rise

0 20 40 60 80 100

Annual branch mortality for ponderosa pine under different thinning regimes

Thinning effect through temporary arrest of crown rise

0 20 40 60 80 100

tive n

Lookout Mountain Pringle Butte

5.5-m spacing

1.8-m spacing

5.5-m spacing

1.8-m spacing

Branch (suppression + tree mortality)Branch (suppression mortality)

Branch + bole mortality

Branch suppression mortality

Branches from tree mortality

Boles from tree mortality

Total cumulative necromass under different initial spacings (Mg/ha)

tive n

0 20 40 60 80 100

Branch (suppression + tree mortality)Branch (suppression mortality)

Branch + bole mortality

Lookout Mountain Pringle FallsLight thinning

Heavy thinning

Light thinning

Heavy thinning

Branch suppression mortality

Branches from tree mortality

Boles from tree mortality

Total cumulative necromass under different thinning regimes (Mg/ha)

Topics

Crown structure

Other silvicultural influencesNeeds and directions

Interwhorl branches

Few interwhorl branches surviving

Douglas-fir crown development from bud set through suppression mortality

Branch measurements by tree climbing

Branch measurements by destructive sampling

Diameter and height of individual Douglas-fir branches

Annual segments of main stem

Douglas-fir

(Maguire et al. 1994)

max branch size

number of branches

relative size of branches

relative position of branches

Reasonable fit to average distribution of branches

Mean of 142 annual stem segments

But how plastic is this distribution with respect to tree attributes affected by silvicultural treatments?

Simulate branch occurrence as inhomogeneous Poisson process

Changing Poisson mean, λ

Changing probability of bud set or branch initiation

Poisson regression with log link function (generalized linear model)

η = ln(λ) = β0 + β1X1 + β2X2 + . . . + βkXk

where λ = mean of Poisson distribution

Annual height growth

Live crown length

Long stem segment (rapid growth)

Response of interwhorl branches in Douglas-fir to thinning

more non-nodal buds

same number of nodal buds

control thinned

0 2 4 6 8 10 12 14 16 18 200.0

Tree 703-878

SimulatedObserved

Branch diameter (mm)

Simulation of primary branching structure, stochastic or otherwise

0 10 20 30

Pinus contorta

Tsgua heterophylla

Pseudotsuga menziesii

Pinus ponderosa

Abies grandis

Larix laricina

Maximum branch diameter profiles

0 5 10 15 20 25 30 35

Tsuga heterophylla

Larix decidua x leptolepis

Pseudotsuga menziesii

Abies grandis

Pinus ponderosa

Pinus contorta

Number of primary branches per meter of stem

clonaltamarack

westernhemlock

grand fir Douglas-fir lodgepolepine

red spruce mesicponderosa

dryponderosa

Species

Highest in clonal tamarack

Most variable in Douglas-fir (but largest sample size)

Topics

Crown structure

Driving forces

Needs and Directions

Improved G&Y models with dynamic link to determinants of stand productivity

Predicting response of forests to climate change

Estimating net primary production and sustainable level of biomass as energy feedstock

Designing fire resistant stands and landscapes

Specifics

Needs and Directions

Crown profiles to better characterize distribution of foliage and non-photosynthetic tissues, leaf area density, crown bulk density

Age class dynamics and implications for photosynthetic efficiency

Nutrient content with respect to sampling and requirements for optimal nutrition

Foliage sampling in CIPS fertilization trials

Thanks to Doug Mainwaring for assistance with many past and ongoing projects

Thank YOU for your kind attention !

0 10 20 30

Western hemlock (Tsuga heterophylla)

less visible pattern in size and distribution

annual segments end in one large branch

western hemlock

0 10 20 30

Height

Clonal tamarack (Larix laricina)

similar to Douglas-fir, although no distinct whorl

Lodgepole pine (Pinus contorta)

distinct whorls, but this species can have two cycles in some years (polycyclic)

ponderosa pine (Pinus ponderosa)

very consistent unicyclic whorl structure

relative uniformity in branch size within a whorl

Grand fir (Abies grandis)

structure generally similar to Douglas-fir, but whorl branches attached at almost exactly the same height (horizontal branch angles)

Simulate branch occurrence as inhomogeneous Poisson process

Increasing Poisson mean, λIncreasing probability of bud or branch set

Does stand density regime influence the

number of primary branches initiated along the stem?

number of primary branches surviving along the stem?

Needle primordia within bud of Douglas-fir, set at end of growing season

(branches formed from axillary buds, but bud primordia not initiated until spring)

Axillary bud primordia (initiated ~ April 1):

Aborted

Latent

Vegetative

Seed cone

Pollen cone

vegetative

latentaborted

pollen cone

seed cone

bud primordia

Douglas-fir bud (Allen and Owen):

needle primordia

bud primordia

Percentage of axillary bud primordia that develops into various bud types in Douglas-fir

vegetative

latent

early aborted

seed cone

pollen cone

early aborted

latent

vegetative

buds 14.1 15.7 8.7 10.9 11.3 6.7

age 50 30 15 50 30 15

Allen and Owen

A - Extended bud of Douglas-fir

B - Extended bud with scales and some needles removed

Developing axillary bud

number of bud primordia initiated or

surviving along the stem?

Apparently not known (?)

number of primary branches initiated or

surviving along the stem?

Limited evidence does suggest that number of branches per length of stem does respond to growing conditions.

Response of precommercially thinned Douglas-fir relative to unthinned controls

non-nodal buds

nodal buds(Maguire 1983)

Terminal leadergrowth

Branch leader growth Terminal nodal buds Terminal non-nodalbud density

Lateral nodal buds Lateral non-nodalbud density

Attribute

l density of non-nodal branches

Maguire 1983

Response of precommercially thinned Douglas-fir relative to unthinned controls

more non-nodal buds

same number of nodal buds

control thinned

Lookout Mountain

Kelsey

Anomalies

Landscape canopy complexity and continuity

Anomalies

Kapur in Malaysia (Dryobalanops spp. )

Bulk density

Potential for simulating the process by which are buds set in a select few leaf axilsBranch position by height and azimuth

Particularly appealing for Pseudotsuga, Abies, Picea species that have interwhorl branches grading into whorl branches

Pont (2001) Use of phyllotaxis to predict arrangement and size of branches in Pinus radiata.

2010 Western Mensurationists Meeting Response of crown and canopy structure to stand density regime...

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