Patterns of leaf area index during stand development in even-aged balsam fir – red spruce stands

2010 ◽  
Vol 40 (4) ◽  
pp. 629-637 ◽  
Author(s):  
R. Justin DeRose ◽  
Robert S. Seymour
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Abies Balsamea ◽  
Stand Density ◽  
Red Spruce ◽  
Balsam Fir ◽  
Research Network ◽  
Site Quality ◽  
Area Index ◽  
Commercial Thinning

Leaf area index (LAI) strongly controls forest stand production. Silviculturists can easily manage this biologically important variable by quantifying its relationship to more directly manageable stand elements, such as density. Hypothesized patterns of LAI development over relative stand density (RD) in even-aged stands of balsam fir ( Abies balsamea (L.) Mill.) and red spruce ( Picea rubens Sarg.) were examined using 78 plots from the Cooperative Forestry Research Unit’s Commercial Thinning Research Network located in the Acadian forest zone in Maine. Nonlinear regression indicated that LAI was significantly related to RD, site quality, and stand top height. LAI increased nonlinearly with increasing RD holding stand top height constant. At a given RD, LAI peaked at approximately 13 m in stand top height. Site quality positively and linearly influenced LAI, but this was only apparent after crown closure, which in turn was influenced by initial stand density. Five-year trajectories of LAI–RD remeasurement data showed an increase in LAI and RD for all stands that varied by stand top height and site quality. Taken together, RD, stand top height, and site quality are strong predictors of LAI and can be used by silviculturists to manage for LAI.

Comparing site quality indices and productivity in ponderosa pine stands of western Montana

1988 ◽  
Vol 18 (3) ◽  
pp. 346-352 ◽  
Author(s):  
Scott D. McLeod ◽  
Steven W. Running
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Ponderosa Pine ◽  
Volume Growth ◽  
Stand Density ◽  
Site Index ◽  
Site Quality ◽  
Area Index ◽  
Water Index ◽  
Available Water

Four indices of site quality were compared with volume growth of pure, ideal ponderosa pine (Pinusponderosa Laws.) stands in western Montana. Indices based on quantifying the biophysical factors or physiological processes that control productivity (available water index and a relative index of seasonal photosynthesis from computer simulations) worked as well as those based on tree or stand measurements (site index and leaf area index). The following correlations of mean annual stem volume increment were found: with leaf area index, R2 = 0.93; with available water index, R2 = 0.95; with site index, R2 = 0.98; with gross photosynthesis R2 = 0.96. The available water and photosynthesis indices were also highly correlated to site index (R2 > 0.95). However, the tree-dependent site quality indices varied by stand density. Leaf area index and volume growth increased with stand density while site index decreased. Simulations indicated that depletion of soil water effectively halted transpiration and photosynthesis by midsummer and illustrated that even with adequate water, cold spring and fall temperatures ultimately defined the length of the growing season and hence site quality. We conclude that an ecosystem process model can provide an index to site quality independent of tree or stand measurements.

scholarly journals Light dynamics and free-to-grow standards in aspen-dominated mixedwood forests

2002 ◽  
Vol 78 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Victor J Lieffers ◽  
Bradley D Pinno ◽  
Kenneth J Stadt
Keyword(s):  
Leaf Area Index ◽  
Key Words ◽  
Leaf Area ◽  
Light Transmission ◽  
Stand Density ◽  
Canopy Gaps ◽  
Light Competition ◽  
Area Index ◽  
Mixedwood Forests ◽  
Key Words Competition

This study examines light competition between aspen and spruce during the sequence of aspen development. Leaf area index and light transmission were measured or estimated for aspen stands from 2 to 125 years old. Light transmission was lowest at 15-25 years, and in some stands, transmission was less than 5% of above-canopy light. Hypothetical aspen stands with various stem configurations and heights were developed, and positions were identified that would meet or fail Alberta free-to-grow (FTG) standards. Light transmission was estimated at each position with the MIXLIGHT forest light simulator. Positions in canopy gaps or at the northern sides of canopy gaps had higher light. In general, however, there was little difference in available light between positions that met or failed FTG criteria. Stand density and size of aspen trees appears to be a better index to predict light transmission and spruce success in juvenile aspen stands than current FTG criteria. Key words: competition, free to grow, hardwood, spruce, light

scholarly journals Evaluations of In-Furrow Insecticides and Fungicides, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 241-241
Author(s):  
Gene Burris ◽  
Don Cook ◽  
B. R. Leonard ◽  
J. B. Graves ◽  
J. Pankey
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Pest Control ◽  
Cotton Seed ◽  
Stand Density ◽  
Research Station ◽  
Area Index ◽  
Seed Rate

Abstract The test was conducted at the Northeast Research Station in St. Joseph, LA. Plots were replicated 4 times in a RCB design and were four rows (40-inch spacing) X 65 ft. ‘Stoneville LA 887’ cotton seed was planted 2 and 3 May on a commerce silt soil which was fertilized sidedress with 90 lb N/acre. Cotton seed were planted with a John Deere model 7100 series planter which was equipped with 10 inch seed cones mounted to replace the seed hoppers. The seed rate was 4 seed/row ft. Granular in-furrow treatments were applied with 8 inch belt cone applicators mounted to replace the standard granular applicators. Control of thrips and aphids was evaluated on 5 randomly selected plants/plot. Evaluations were made on 18, 19, 24, 26, and 29 May and 8 Jun. Plant height counts were taken on 10 randomly selected plants/plot on 8 Jun. Stand density and leaf area was determined by counting the number of plants in a randomly selected meter on 29 May. Leaf area was recorded using a Li Cor leaf area machine. The data was recorded as cm2 and converted to a leaf area index (LAI). Major pests and/or secondary pest control was initiated in Jun and continued on an “as needed” basis through Aug.

scholarly journals Leaf Area and Structural Changes after Thinning in Even-AgedPicea rubensandAbies balsameaStands in Maine, USA

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
R. Justin DeRose ◽  
Robert S. Seymour
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Structural Changes ◽  
Abies Balsamea ◽  
Picea Rubens ◽  
Area Index ◽  
Precommercial Thinning ◽  
Density Reduction

We tested the hypothesis that changes in leaf area index (LAI m2 m−2) and mean stand diameter following thinning are due to thinning type and residual density. The ratios of pre- to postthinning diameter and LAI were used to assess structural changes between replicated crown, dominant, and low thinning treatments to 33% and 50% residual density in even-agedPicea rubensandAbies balsameastands with and without a precommercial thinning history in Maine, USA. Diameter ratios varied predictably by thinning type: low thinnings were <0.7, crown thinnings were >0.7 but <1.0, and dominant thinnings were >1.0 . LAI change was affected by type and intensity of thinning. On average, 33% density reduction removed <50% of LAI, whereas 50% density reduction removed >50% of LAI. Overall reduction of LAI was generally greatest in dominant thinnings (54%), intermediate in crown thinnings (46%), and lowest in low thinnings (35%). Upon closer examination by crown classes, the postthinning distribution of LAI between upper and lower crown classes varied by thinning history, thinning method, and amount of density reduction.

Sun and shade leaves: clues to how salal (Gaultheriashallon) responds to overstory stand density

1991 ◽  
Vol 21 (3) ◽  
pp. 300-305 ◽  
Author(s):  
N. J. Smith
Keyword(s):  
Leaf Area Index ◽  
Relative Density ◽  
Leaf Area ◽  
Stand Density ◽  
Leaf Biomass ◽  
Area Index ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

Salal (Gaultheriashallon Pursh) leaf biomass, leaf area index, specific leaf area, and leaf morphology were examined in 13 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands from 37 destructively measured 1-m2 quadrats. In response to light and stand overstory density, salal shoots produced either mainly sun leaves or mainly shade leaves. Sun leaves were associated with sunflecks in open-grown or variably stocked stands. Shade leaves were associated with diffuse light under denser stands. Sun-leaf quadrats had mean specific leaf areas less than 90 cm2/g; shade-leaf quadrats had mean specific leaf areas greater than 90 cm2/g. Sun leaves were narrower, with average leaf widths less than 5 cm. Quadrat salal leaf biomass and leaf area index peaked at Curtis' metric relative density 5.9, which corresponded to an availability of 15% of global photosynthetically active radiation. Sun-leaf quadrats occurred below relative density 5; shade-leaf quadrats occurred above relative density 4. A mixture of sun- and shade-leaf quadrats occurred between about relative density 4 and 5, depending on the uniformity of stocking.

The role of stand density on growth efficiency, leaf area index, and resin flow in southwestern ponderosa pine forests

2007 ◽  
Vol 37 (2) ◽  
pp. 343-355 ◽  
Author(s):  
Nate G. McDowell ◽  
Henry D. Adams ◽  
John D. Bailey ◽  
Thomas E. Kolb
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Ponderosa Pine ◽  
Basal Area ◽  
Stand Density ◽  
Growth Efficiency ◽  
Resin Flow ◽  
Area Index ◽  
Sapwood Area ◽  
Ponderosa Pine Forests

We examined the response of growth efficiency (GE), leaf area index (LAI), and resin flow (RF) to stand density manipulations in ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) forests of northern Arizona, USA. The study used a 40 year stand density experiment including seven replicated basal area (BA) treatments ranging from 7 to 45 m2·ha–1. Results were extended to the larger region using published and unpublished datasets on ponderosa pine RF. GE was quantified using basal area increment (BAI), stemwood production (NPPs), or volume increment (VI) per leaf area (Al) or sapwood area (As). GE per Al was positively correlated with BA, regardless of numerator (BAI/Al, NPPs/Al, and VI/Al; r2 = 0.84, 0.95, and 0.96, respectively). GE per As exhibited variable responses to BA. Understory LAI increased with decreasing BA; however, total (understory plus overstory) LAI was not correlated with BA, GE, or RF. Opposite of the original research on this subject, resin flow was negatively related to GE per Al because Al/As ratios decline with increasing BA. BAI, and to a lesser degree BA, predicted RF better than growth efficiency, suggesting that the simplest measurement with the fewest assumptions (BAI) is also the best approach for predicting RF.

Vertical distribution of leaf area in Larixoccidentalis: a comparison of two estimation methods

1989 ◽  
Vol 19 (9) ◽  
pp. 1131-1136 ◽  
Author(s):  
William R. Bidlake ◽  
R. Alan Black
Keyword(s):  
Vertical Distribution ◽  
Leaf Area Index ◽  
Normal Distribution ◽  
Leaf Area ◽  
Stand Density ◽  
Total Leaf Area ◽  
Area Index ◽  
Total Leaf ◽  
Gap Fraction ◽  
The Vertical Distribution

Total leaf-area index and the vertical distribution of leaf-area index were described for an unthinned stand (density 11 250 stems/ha) and a thinned stand (density 1660 stems/ha) of 30-year-old Larixoccidentalis Nutt. Two independent methods were used to estimate leaf-area index in each of the two stands. The first method is based on allometric relationships that are applied to stem measurements, and the second method is based on gap-fraction analysis of fisheye photographs. Leaf-area index estimates obtained by the two methods were not significantly different. The gap-fraction method provides a desirable alternative because much less fieldwork is required, however, use of this method is limited to canopies where the light-blocking elements are randomly displayed. Total leaf-area index values for the unthinned and thinned stands were 5.0 and 3.6, respectively. The vertical distribution of leaf-area index in the unthinned stand resembled a normal distribution. The vertical distribution of leaf-area index in the thinned stand would have resembled a normal distribution, except that thinning operations resulted in a truncated distribution of leaf-area index at the canopy base.

Response of leaf area index to density for two contrasting tree species

1991 ◽  
Vol 21 (12) ◽  
pp. 1760-1764 ◽  
Author(s):  
Steven B. Jack ◽  
James N. Long
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Tree Species ◽  
Lodgepole Pine ◽  
Stand Density ◽  
Area Index ◽  
Subalpine Fir ◽  
Wide Range ◽  
Stable Leaf ◽  
The Relationship

It is commonly assumed that mature forest stands with closed canopies support constant amounts (weight or area) of foliage, independent of stand density. For stand leaf area to be constant, mean leaf area must be plastic with respect to density. We examined the relationship between density and both leaf area index and mean leaf area for two contrasting tree species, lodgepole pine (Pinuscontorta var. latifolia Engelm.) and subalpine fir (Abieslasiocarpa (Hook.) Nutt.). In lodgepole pine, leaf area index tended to be constant over a wide range of absolute and relative densities, but in subalpine fir, leaf area index increased with density. Consistent with these results, mean leaf area of lodgepole pine was more plastic with respect to density than mean leaf area of subalpine fir. The presumption of stable leaf area index independent of stand density, therefore, may not be as general as usually assumed owing to differential responses of mean leaf area to density. Differences in plasticity between the two species were attributed to differences in relative shade tolerance and the effect of shade on competitive interactions at high densities.

Canopy profiles of some Piedmont hardwood forests

1988 ◽  
Vol 18 (8) ◽  
pp. 1090-1093 ◽  
Author(s):  
Craig Wallace Hedman ◽  
Dan Binkley
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Net Primary Productivity ◽  
Hardwood Forests ◽  
Site Quality ◽  
Aboveground Net Primary Productivity ◽  
Total Leaf Area ◽  
Area Index ◽  
Total Leaf ◽  
Site Fertility

Relationships between canopy profiles and site quality were examined in 11 old, uneven-aged (>180 years) hardwood forests in the Piedmont of eastern North Carolina. Site fertility was indexed by extractable soil calcium and phosphorus, by the content of calcium, phosphorus and nitrogen in litter fall, and by the aboveground net primary productivity of each stand. Canopy profiles were indexed by the leaf area index for each 3.3-m height interval. Total leaf area index correlated highly with most measures of site fertility, but we found no clear patterns between canopy profiles and any measure of site fertility. We conclude that site fertility is reflected in broad ecosystem-level variables such as total leaf area index and stand productivity, but that detailed patterns such as canopy profiles relate strongly to specific stand composition, age structure, and history.

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