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.

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.

scholarly journals Morphological Features Growth and Development of Dendrobium sp. Orchid as Influenced by Nutrient Spray

2012 ◽  
Vol 5 (1) ◽  
pp. 309-318 ◽  
Author(s):  
MI Kabir ◽  
MG Mortuza ◽  
MO Islam
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Leaf Length ◽  
Stem Diameter ◽  
Leaf Number ◽  
Leaf Width ◽  
Total Leaf Area ◽  
Area Index ◽  
Total Leaf

The experiment was conducted to see the effect of nutrient spray on morphophysiological feature and growth of three orchid varieties namely Dendrobium Red Bull, D. Kasim Gold and D White 5 N. Results revealed that the morphophysiological and growth attributes significantly varied among the cultivars. D Red Bull showed the highest plant height, leaf length, leaf area and stem diameter among the varieties. D. White 5 N was superior in leaf number and total leaf area and D. Kasim Gold was superior in leaf area index and leaf width to the other varieties. On the other hand, the trend of increasing in leaf length, leaf width, leaf area index, leaf number, leaf area and total leaf area was the highest for N:P:K as 10:25:30. Plant height and stem diameter was maximum for N:P:K as 15:20:20. In conclusion, low level of nitrogen and high level of phosphorus and potassium was suitable for leaf length, leaf width, leaf area index, leaf number, leaf area and total leaf area while high level of nitrogen and low level of potassium was suitable for plant height and stem diameter. DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11598 J. Environ. Sci. & Natural Resources, 5(1): 309-318, 2012

Soybean (Glycine max) Interference on Common Cocklebur (Xanthium strumarium) and Entireleaf Morningglory (Ipomoea hederaceavar.integriuscula)

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 402-409 ◽  
Author(s):  
Dwight G. Mosier ◽  
Lawrence R. Oliver
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Field Experiments ◽  
Xanthium Strumarium ◽  
Treatment Combination ◽  
Total Leaf Area ◽  
Area Index ◽  
Total Leaf ◽  
The Common

Field experiments were conducted to evaluate soybean interference on common cocklebur and entireleaf morningglory under irrigated and nonirrigated conditions. Interference from the mixture of soybean and entireleaf morningglory, and soybean alone reduced the total leaf area index (LAI), LAI within the common cocklebur canopy, and growth rate of common cocklebur more than did entireleaf morningglory; more reduction occurred without irrigation than with irrigation. Irrigated common cocklebur produced 687 burs per plant, while nonirrigated produced 359. Irrigated and nonirrigated soybeans and the mixture of soybeans and entireleaf morningglory reduced common cocklebur bur production 43 to 47%. Irrigated entireleaf morningglory reduced common cocklebur bur production 42%, while nonirrigated reduced bur production 28%. Interference from the mixture of irrigated soybeans and common cocklebur reduced the total leaf area index (LAI), LAI within the entireleaf morningglory canopy, and growth rate of entireleaf morningglory more than did soybean or common cocklebur alone. Irrigated entireleaf morningglory produced 542 and 1107 seeds per plant in 1982 and 1983, respectively. The mixture of irrigated soybeans and common cocklebur reduced entireleaf morningglory seed production 84 to 90%. Nonirrigated entireleaf morningglory was not competitive in any treatment combination either year due to lack of sufficient LAI.

Effects of clumping on estimates of stand leaf area index using the LI-COR LAI-2000

1993 ◽  
Vol 23 (9) ◽  
pp. 1940-1943 ◽  
Author(s):  
N. J. Smith ◽  
J. M. Chen ◽  
T. A. Black
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Ground Surface ◽  
Stand Density ◽  
Plant Canopy ◽  
Allometric Relationships ◽  
Total Leaf Area ◽  
Area Index ◽  
Second Growth ◽  
Wide Range

Eighteen natural second-growth stands of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) from a wide range of stand densities and stocking levels were measured for stand leaf area index (LAI) from allometric relationships (direct LAI) and the LI-COR LAI-2000 plant canopy analyzer (indirect LAI). LAI was based on one-half total leaf area (m2) per square metre of ground surface area, normal to any slope. The LAI-2000 underestimated direct LAI by 62%. The underestimate of LAI was due to the confinement of needles within branches (74%) and nonrandom branch distribution (26%). In effect, the branches behaved like big leaves. The LAI-2000 can be used to estimate LAI across a variety of stand density and stocking levels by using a single stand clumping factor of 2.63.

scholarly journals Extracting Leaf Area Index Using Viewing Geometry Effects - A New Perspective on High-Resolution Unmanned Aerial System Photography.

2020 ◽  
Author(s):  
Lukas Roth ◽  
Helge Aasen ◽  
Achim Walter ◽  
Frank Liebisch
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Ecology ◽  
Growth And Yield ◽  
Unmanned Aerial System ◽  
Area Index ◽  
Handheld Device ◽  
Gap Fraction ◽  
Rgb Images ◽  
New Perspective

Abstract Extraction of leaf area index (LAI) is an important prerequisite in numerous studies related to plant ecology, physiology and breeding. LAI is indicative for the performance of a plant canopy and of its potential for growth and yield. In this study, a novel method to estimate LAI based on RGB images taken by an unmanned aerial system (UAS) is introduced. Soybean was taken as the model crop of investigation. The method integrates viewing geometry information in an approach related to gap fraction theory. A 3-D simulation of virtual canopies helped developing and verifying the underlying model. In addition, the method includes techniques to extract plot based data from individual oblique images using image projection, as well as image segmentation applying an active learning approach. Data from a soybean field experiment were used to validate the method. The thereby measured LAI 14 prediction accuracy was comparable with the one of a gap fraction-based handheld device (R2 of 0.92, RMSE of 0.42 m2 m2) and correlated well with destructive LAI measurements (R2 of 0.89, RMSE of 0.41 m2 m2). These results indicate that, if respecting the range (LAI ≤3) the method was tested for, extracting LAI from UAS derived RGB images using viewing geometry information represents a valid alternative to destructive and optical handheld device LAI measurements in soybean. Thereby, we open the door for automated, high-throughput assessment of LAI in plant and crop science.

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

Use of airborne lidar for estimating canopy gap fraction and leaf area index of tropical montane forests

2015 ◽  
Vol 36 (10) ◽  
pp. 2569-2583 ◽  
Author(s):  
Janne Heiskanen ◽  
Lauri Korhonen ◽  
Jesse Hietanen ◽  
Petri K.E. Pellikka
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Canopy Gap ◽  
Airborne Lidar ◽  
Montane Forests ◽  
Area Index ◽  
Tropical Montane Forests ◽  
Gap Fraction

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.

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