A comparison of four methods for determining leaf area index in successional hardwood forests

1985 ◽  
Vol 15 (6) ◽  
pp. 1154-1158 ◽  
Author(s):  
Thomas W. Jurik ◽  
George M. Briggs ◽  
David M. Gates
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Hardwood Forests ◽  
Litter Fall ◽  
Area Index ◽  
Tree Diameter ◽  
Leaf Mass ◽  
The Vertical Distribution ◽  
Harvest Method ◽  
Do So

Four methods of determining leaf area index of three successional hardwood forests in northern lower Michigan were compared. Direct harvests gave values for leaf area index ranging from 1.4 to 3.6. Estimates of leaf area index derived from litter fall data were consistently higher than the harvest values and were highly dependent on the ratio of leaf area to leaf mass, which had to be estimated. A visual method using sightings through a tube gave values consistently lower (by 27–42%) than the harvest values. Calculations of leaf area index based on regressions of leaf mass versus tree diameter gave results very close to the harvest values for each site as a whole; calculations for smaller plots were more variable. The harvest method allowed measurement of the vertical distribution of leaf area; the other methods could not do so.

Leaf heteroblasty in eucalypts: biogeographic evidence of ecological function

2018 ◽  
Vol 66 (3) ◽  
pp. 191 ◽  
Author(s):  
Carolyn Vlasveld ◽  
Benjamin O'Leary ◽  
Frank Udovicic ◽  
Martin Burd
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Unit Area ◽  
Leaf Shape ◽  
Eucalyptus Species ◽  
Canopy Closure ◽  
Area Index ◽  
Leaf Mass ◽  
Adult Leaf ◽  
Shape And Size

Leaves that develop on seedlings, young saplings or regenerative shoots of many eucalypt species are strikingly different in morphology from the typical leaves of more mature plants; a developmental pattern known as heteroblasty. We measured dimorphism between juvenile and adult leaves in shape and size, leaf mass per unit area, and vein frequency in a continent-wide sample of Angophora, Corymbia and Eucalyptus species. We tested whether heteroblasty in this group is an adaptation to shading by comparing the degree of juvenile–adult leaf dimorphism with the canopy closure (measured by the leaf area index) of the habitat in which species occurred. No pattern emerged for heteroblasty in leaf shape and size or leaf mass per unit area, but there was a significant relationship (accounting for phylogenetic relationships) between the degree of juvenile–adult dimorphism in vein frequency and habitat leaf area index. Juvenile leaves tended to have more widely spaced veins than adult leaves of the same species, in regions with more closed vegetative canopies. This evidence suggests that eucalypt heteroblasty is, at least in part, a hydraulic adaptation to the different conditions faced by younger and older plants in higher productivity regions with denser vegetation.

scholarly journals Global Assimilation of Remotely Sensed Leaf Area Index: The Impact of Updating More State Variables Within a Land Surface Model

2022 ◽  
Vol 3 ◽  
Author(s):  
Azbina Rahman ◽  
Xinxuan Zhang ◽  
Paul Houser ◽  
Timothy Sauer ◽  
Viviana Maggioni
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Land Surface ◽  
Land Surface Model ◽  
Net Ecosystem Exchange ◽  
Surface Model ◽  
Random Errors ◽  
Area Index ◽  
Leaf Mass ◽  
The Impact

As vegetation regulates water, carbon, and energy cycles from the local to the global scale, its accurate representation in land surface models is crucial. The assimilation of satellite-based vegetation observations in a land surface model has the potential to improve the estimation of global carbon and energy cycles, which in turn can enhance our ability to monitor and forecast extreme hydroclimatic events, ecosystem dynamics, and crop production. This work proposes the assimilation of a remotely sensed vegetation product (Leaf Area Index, LAI) within the Noah Multi-Parameterization land surface model using an Ensemble Kalman Filter technique. The impact of updating leaf mass along with LAI is also investigated. Results show that assimilating LAI data improves the estimation of transpiration and net ecosystem exchange, which is further enhanced by also updating the leaf mass. Specifically, transpiration anomaly correlation coefficients improve in about 77 and 66% of the global land area thanks to the assimilation of leaf area index with and without updating leaf mass, respectively. Random errors in transpiration are also reduced, with an improvement of the unbiased root mean square error in 70% (74%) of the total area without the update of leaf mass (with the update of leaf mass). Similarly, net ecosystem exchange anomaly correlation coefficients improve from 52 to 75% and random errors improve from 49 to 62% of the total pixels after the update of leaf mass. Better performances for both transpiration and net ecosystem exchange are observed across croplands, but the largest improvement is shown over forests and woodland. The global scope of this work makes it particularly important in data poor regions (e.g., Africa, South Asia), where ground observations are sparse or not available altogether but where an accurate estimation of carbon and energy variables can be critical to improve ecosystem and crop management.

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.

Vertical leaf area distribution, light transmittance, and application of the Beer–Lambert Law in four mature hardwood stands in the southern Appalachians

1995 ◽  
Vol 25 (6) ◽  
pp. 1036-1043 ◽  
Author(s):  
James M. Vose ◽  
Barton D. Clinton ◽  
Neal H. Sullivan ◽  
Paul V. Bolstad
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Independent Set ◽  
Light Transmittance ◽  
Litter Fall ◽  
Validation Data ◽  
Area Index ◽  
Vertical Leaf ◽  
Area Distribution ◽  
Leaf Area Distribution

We quantified stand leaf area index and vertical leaf area distribution, and developed canopy extinction coefficients (k), in four mature hardwood stands. Leaf area index, calculated from litter fall and specific leaf area (c2•g−1), ranged from 4.3 to 5.4 m2•m−2. In three of the four stands, leaf area was distributed in the upper canopy. In the other stand, leaf area was uniformly distributed throughout the canopy. Variation in vertical leaf area distribution was related to the size and density of upper and lower canopy trees. Light transmittance through the canopies followed the Beer–Lambert Law, and k values ranged from 0.53 to 0.67. Application of these k values to an independent set of five hardwood stands with validation data for light transmittance and litter-fall leaf area index yielded variable results. For example, at k = 0.53, calculated leaf area index was within ± 10% of litter-fall estimates for three of the five sites, but from −35 to + 85% different for two other sites. Averaged across all validation sites, litter-fall leaf area index and Beer-Lambert leaf area index predictions were in much closer agreement ( ± 7 to ± 15%).

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.

Variation in leaf area index and stand leaf mass of European beech across gradients of soil acidity and precipitation

Plant Ecology ◽  
2006 ◽  
Vol 186 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Christoph Leuschner ◽  
Sylvia Voß ◽  
Andrea Foetzki ◽  
York Clases
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Soil Acidity ◽  
European Beech ◽  
Area Index ◽  
Leaf Mass
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