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 Silviculture College of Forestry Oregon 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 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

Why crown structure ? Crown and canopy structure of western conifers Crown size drives growth and vigor

Why crown structure ? Crown and canopy structure of western conifers Crown size and its aggregate as canopy structure is key element in wildlife habitat (structural diversity) Crown area profile height Crown area

Why crown structure ? Crown and canopy structure of western conifers Crown size influences wood quality (branch size, crown wood core, microanatomy )? Josza and Middleton 1994 Branch diameter Crown wood core

Why crown structure ? Crown and canopy structure of western conifers Crowns ARE the tree-atmosphere interface (gas and heat exchange, light interception)

Why crown structure ? Crown and canopy structure of western conifers Crowns represent potentially utilizable biomass (biofuel feedstock) $

Why crown structure ? Crown and canopy structure of western conifers 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? Resolution of crown structure for differing objectives

Crown length and crown width and biomass? Resolution of crown structure for differing objectives (leaf, branch,...)

First-order (primary) branches? Resolution of crown structure for differing objectives

Branches of all orders with detailed spatial information ? Resolution of crown structure for differing objectives

Spatial structure of all branches and leaves, or all structural modules ? Resolution of crown structure for differing objectives

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 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

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

Pringle Butte ponderosa pine x lodgepole pine spacing trial 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 trials Garber and Maguire 2004 Forest Science Standing volume ~proportional to initial spacing

Mixed species spacing trials Periodic annual increment starting to level out across spacings yrs yrs yrs

Mixed species spacing trials Interaction of spacing and species composition on relative height development. LP PP GF

Vs. Mixed species spacing trials 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

Mixed species spacing trials Relative amount of foliage Shift in relative foliage and branch distribution among different initial spacings influence spatial pattern in crown bulk density

Pringle Butte ponderosa pine x lodgepole pine spacing trial

LP PP

Pringle Butte ponderosa pine x lodgepole pine spacing trial LP PP

Pringle Butte ponderosa pine x lodgepole pine spacing trial LP PP

Vs. Spacing effects on crown recession More rapid recession at closer spacings implies: -Loss of biomass - Accumulation of fuel

Ponderosa pine simulations based on initial conditions at Pringle & Lookout Three initial spacings grown out 100 years: 6-ft 12-ft 18-ft Thinning at years 25, 50 and 75, and all grown out 100 years: Residual SDI (% of max): 55% 41% 27% TPH SDI DBH HT

Ponderosa pine simulations based on initial conditions at Pringle & Lookout Number of branches Branch necromass Branch diameter

Annual branch mortality for ponderosa pine under different initial spacings Spacing effects through: - Time to crown closure - Rate of height growth after closure

Annual branch mortality for ponderosa pine under different initial spacings Site quality effect through rate of height growth  rate of crown rise

Annual branch mortality for ponderosa pine under different thinning regimes Thinning effect through temporary arrest of crown rise

Branch suppression mortality Branches from tree mortality Boles from tree mortality Total cumulative necromass under different initial spacings (Mg/ha)

Branch suppression mortality Branches from tree mortality Boles from tree mortality Total cumulative necromass under different thinning regimes (Mg/ha)

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

buds 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) = β 0 + β 1 X 1 + β 2 X β k X k 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

Simulation of primary branching structure, stochastic or otherwise

Pinus contorta Tsgua heterophylla Pseudotsuga menziesii Pinus ponderosa Abies grandis Larix laricina

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

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

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 !

Western hemlock (Tsuga heterophylla) less visible pattern in size and distribution

annual segments end in one large branch western hemlock

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, λ Increasing probability of bud or branch set

Does stand density regime influence the number of primary branches initiated along the stem? Does stand density regime influence the 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 latent aborted 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 age Allen and Owen

A - Extended bud of Douglas-fir B - Extended bud with scales and some needles removed Developing axillary bud

Does stand density regime influence the number of bud primordia initiated or surviving along the stem? Apparently not known (?)

Does stand density regime influence the 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)

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 axils  Branch 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.