Influence of canopy structure on the understory environment in tall, old-growth, conifer forests

2000 ◽  
Vol 30 (8) ◽  
pp. 1231-1245 ◽  
Author(s):  
Robert Van Pelt ◽  
Jerry F Franklin
Keyword(s):  
Leaf Area ◽  
Canopy Structure ◽  
Field Measurements ◽  
Horizontal Distribution ◽  
Shrub Cover ◽  
Old Growth ◽  
Light Levels ◽  
Vertical Heterogeneity ◽  
Canopy Volume ◽  
Old Growth Forests

The effect of the spatial distribution of trees and foliage on understory conditions was examined in six tall old-growth forests along the Pacific Coast: two sites each in Washington, Oregon, and California. Detailed field measurements of crown parameters were collected on over 9000 trees encompassing over 14.5 ha in the stands. Crown parameters were used to construct a spatially explicit model useful in analyzing the variability of crown distributions in both vertical and horizontal dimensions. Sapwood measurements of over 400 trees in combination with published equations and 240 hemispherical photos were used to assess leaf area and understory light levels, respectively. Shrub and herb cover was used as a biological indicator of growing conditions in the understory. Although leaf area is often assumed to be correlated with the amount of light penetrating the canopy, this is not the case in tall, old-growth forests. The semivariance of the horizontal distribution of canopy volume was strongly correlated with shrub cover and understory light levels and was an overall predictor of canopy structure. This variability gives rise to potentially higher understory light levels and shrub cover values when compared with a forest lacking this vertical heterogeneity and may allow the stand to support a higher volume of foliage.

Determinants of leaf area index and understorey light availability in New Zealand old‐growth forests

2020 ◽  
Vol 47 (4) ◽  
pp. 941-954
Author(s):  
Rocío Fritz ◽  
Christopher H. Lusk
Keyword(s):  
New Zealand ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Light Availability ◽  
Old Growth ◽  
Area Index ◽  
Old Growth Forests

Greater risk of physical damage caused by debris fall to understory plants and tree seedlings in old-growth forests than in young forests

2013 ◽  
Vol 43 (12) ◽  
pp. 1203-1206 ◽  
Author(s):  
Andrew J. Larson
Keyword(s):  
Woody Debris ◽  
Canopy Structure ◽  
Snow Accumulation ◽  
Stand Age ◽  
Tree Seedlings ◽  
Physical Damage ◽  
Old Growth ◽  
Understory Plants ◽  
Old Growth Forests ◽  
Young Forests

Falling canopy debris causes injury and mortality of tree seedlings and understory plants in a wide variety of forests. Canopy structure and dynamics differ between young and old-growth forests: old forests are taller and have more aboveground biomass and greater annual mortality of bole biomass. I predicted that risk of damage caused by debris fall in the understory is greater in old-growth forests than in young forests. I tested this prediction by tracking for 1 year the fates of artificial seedlings placed in young (stand age 31 to 61 years) and old-growth (stand age circa 500 years) Pseudotsuga–Tsuga forests. The risk of physical damage caused by debris fall in old-growth forests was significantly greater than in young forests (P = 0.001). Seedling models were damaged by falling debris at a rate of 4.4%·year−1 and 0.8%·year−1 in old-growth and young forests, respectively. More seedling models were damaged by fallen coarse woody debris in old-growth forests than in young forests, although this trend was not significant (P = 0.134). Approximately 25% of seedling models in both young and old-growth forests were damaged by something other than fallen canopy debris, most likely snow accumulation.

Comparing nondestructive measures of forage structure and phytomass

2000 ◽  
Vol 80 (3) ◽  
pp. 565-573 ◽  
Author(s):  
B. E. Olson ◽  
R. T. Wallander ◽  
J. M. Beaver
Keyword(s):  
Radiative Transfer ◽  
Leaf Area ◽  
Canopy Structure ◽  
Plant Canopy ◽  
Native Range ◽  
Area Index ◽  
Crested Wheatgrass ◽  
Canopy Volume ◽  
Peak Standing Crop ◽  
Intercepted Radiation

Nondestructive radiative transfer and canopy volume methods were compared with the destructive hand-clipping method to determine forage structure and phytomass. On a native range site, fifteen 1-m2 circular plots were located at each of five microsites. On a crested wheatgrass site, thirty 1-m2 plots were located in grazed and in ungrazed areas. At peak standing crop, all plots were measured with a LI-COR Plant Canopy Analyzer to determine leaf area index (LAI), diffuse non-intercepted radiation (DNIR), and mean tilt angle (MTA) of leaves. Then, plants within plots were measured with a ruler to determine volume. Finally, all phytomass within plots was harvested. At the native range site, plant volume was related with LAI and DNIR on four of five microsites. Phytomass was related with LAI and DNIR on two microsites. At the crested wheatgrass site, volume and phytomass were related with LAI, DNIR, and MTA on grazed plots. Only phytomass was related with LAI and DNIR on ungrazed plots. The Plant Canopy Analyzer measures canopy structure and phytomass; it is fast, and its data are transferred directly to a computer. Measuring plant volume is inexpensive and requires minimal training. Determining phytomass by clipping is accurate and requires minimal training, but it is time-consuming and destructive. Key words: Leaf area, canopy, volume, phytomass, radiative transfer

scholarly journals Physical structure and biological composition of canopies in tropical secondary and old-growth forests

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256571
Author(s):  
David B. Clark ◽  
Steven F. Oberbauer ◽  
Deborah A. Clark ◽  
Michael G. Ryan ◽  
Ralph O. Dubayah
Keyword(s):  
Leaf Area ◽  
Canopy Structure ◽  
Physical Structure ◽  
Canopy Height ◽  
Old Growth ◽  
Area Index ◽  
Old Growth Forest ◽  
Free Air ◽  
Leaf Density ◽  
Patch Scale

The area of tropical secondary forests is increasing rapidly, but data on the physical and biological structure of the canopies of these forests are limited. To obtain such data and to measure the ontogeny of canopy structure during tropical rainforest succession, we studied patch-scale (5 m2) canopy structure in three areas of 18–36 year-old secondary forest in Costa Rica, and compared the results to data from old-growth forest at the same site. All stands were sampled with a stratified random design with complete harvest from ground level to the top of the canopy from a modular portable tower. All canopies were organized into distinct high- and low-leaf-density layers (strata), and multiple strata developed quickly with increasing patch height. The relation of total Leaf Area Index (LAI, leaf area per area of ground) to patch canopy height, the existence of distinct high and low leaf- density layers (strata and free air spaces), the depth and LAI of the canopy strata and free air spaces, and the relation of the number of strata to patch canopy height were remarkably constant across the entire successional gradient. Trees were the most important contributor to LAI at all stages, while contribution of palm LAI increased through succession. We hypothesize that canopy physical structure at the patch scale is driven by light competition and discuss how this hypothesis could be tested. That canopy physical structure was relatively independent of the identity of the species present suggests that canopy physical structure may be conserved even as canopy floristics shift due to changing climate.

GLOBAL LEAF AREA INDEX DATA FROM FIELD MEASUREMENTS, 1932-2000

2001 ◽  
Author(s):  
G. P. ASNER ◽  
S. T. GOWER ◽  
J. M. O. SCURLOCK
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Field Measurements ◽  
Area Index ◽  
Index Data

Northwest Forest Plan–the first 15 years (1994–2008): status and trends of late-successional and old-growth forests

2011 ◽  
Author(s):  
Melinda Moeur ◽  
Janet L. Ohmann ◽  
Robert E. Kennedy ◽  
Warren B. Cohen ◽  
Matthew J. Gregory ◽  
...  
Keyword(s):  
Old Growth ◽  
Status And Trends ◽  
Old Growth Forests ◽  
Northwest Forest Plan

Alternatives to clearcutting in the old-growth forests of southeast Alaska: study plan and establishment report.

2000 ◽  
Author(s):  
Michael H. McClellan ◽  
Douglas N. Swanston ◽  
Paul E. Hennon ◽  
Robert L. Deal ◽  
Toni L. de Santo ◽  
...  
Keyword(s):  
Old Growth ◽  
Southeast Alaska ◽  
Old Growth Forests ◽  
Study Plan

Multi‐decade tree mortality in temperate old‐growth forests of Europe and North America: Non‐equilibrial dynamics and species‐individualistic response to disturbance

2021 ◽  
Author(s):  
Kerry D. Woods ◽  
Thomas A. Nagel ◽  
Bogdan Brzeziecki ◽  
C. Mark Cowell ◽  
Dejan Firm ◽  
...  
Keyword(s):  
North America ◽  
Tree Mortality ◽  
Old Growth ◽  
Old Growth Forests
Sign in / Sign up

Export Citation Format

Share Document