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

Comparison of Methods of Estimating Leaf-Area Index In Old-Growth Douglas-Fir

Ecology ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 975-979 ◽  
Author(s):  
J. D. Marshall ◽  
R. H. Waring
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Douglas Fir ◽  
Comparison Of Methods ◽  
Old Growth ◽  
Area Index

scholarly journals The effect of light availability on leaf area index, biomass production and plant species composition of park grasslands in Warsaw  

2013 ◽  
Vol 59 (No. 12) ◽  
pp. 543-548 ◽  
Author(s):  
P. Dąbrowski ◽  
B. Pawluśkiewicz ◽  
Kalaji HM ◽  
Baczewska AH
Keyword(s):  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Light Availability ◽  
Vegetation Coverage ◽  
Light Conditions ◽  
Area Index ◽  
Sward Height ◽  
Poa Trivialis ◽  
Leaf Density

How light conditions affect development of park grasslands is a question that has not been satisfactory addressed. The aim of this study was therefore determination of the level to which unfavorable light conditions influence grassy parks area and relationships between parameters which determine state of turf grasses. Researches were conducted in two parks in Warsaw, in various light conditions and included measurement of: leaf density, sward height, leaf area index (LAI), and botanical composition of the communities. The leaf density of shaded areas did not exceed 70%. LAI value varied from 0.5 to 0.9-fold lower than in the areas in half-shade and in sun. The participation of basic lawn species at Skaryszewski Park was higher under shade, while at Łazienki Królewskie was higher in full-sunlight areas. The state of tested grassy areas in limited solar radiation does not satisfy the requirements of recreational and representational functions. The development processes of vegetation coverage were inhibited at the sites of lower solar radiation. LAI was influenced by both leaf coverage and sward height. Agrostis stolonifera and Poa trivialis may be recommended to create grass areas under limited solar radiation.

Leaf area index of an old-growth Douglas-fir forest estimated from direct structural measurements in the canopy

2000 ◽  
Vol 30 (12) ◽  
pp. 1922-1930 ◽  
Author(s):  
Sean C Thomas ◽  
William E Winner
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Understory Vegetation ◽  
Western Hemlock ◽  
Old Growth ◽  
Area Index ◽  
Contact Frequency ◽  
Canopy Access

Leaf area index (LAI) in old-growth Douglas-fir (Pseudotsuga menziesii var menziesii (Mirb.) Franco) forests exceeds that of any other forest ecosystem by some estimates; however, LAI determinations in coniferous forests have generally been indirect, involving extrapolations of patterns observed in younger stands. Aided by a 75-m construction crane for canopy access, we used a vertical line-intercept method to estimate LAI for a [Formula: see text]450-year-old Douglas-fir - western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest in southwestern Washington state. LAI was calculated as the product of foliage contact frequency and an "extinction coefficient" accounting for foliage angular distribution, geometry, and the ratio of "interceptable" to total leaf area. LAI estimates were 9.3 ± 2.1 (estimate ± 95% confidence interval), 8.5 ± 2.2, and 8.2 ± 1.8 in 1997, 1998, and 1999, respectively, or 8.6 ± 1.1 pooled across years. Understory vegetation, including foliage of woody stems <5 cm diameter, represented 20% of this total. Sample points in which Douglas-fir was dominant had a higher total LAI than points dominated by western hemlock, including a higher LAI of understory vegetation. Our results do not support the contention that old-growth Douglas-fir - western hemlock forests maintain an appreciably higher LAI than do other forest ecosystems. Moreover, LAI in very old stands may decline as western hemlock replaces Douglas-fir through the course of succession.

scholarly journals PERTUMBUHAN DAN PRODUKSI PAPRIKA PADA BERBAGAI INTENSITAS RADIASI SURYA DI DATARAN RENDAH, BATAM(GROWTH AND PRODUCTION OF SWEET PEPPER CULTIVATED UNDER DIFFERENT SOLAR RADIATION INTENSITY AT LOWLAND REGION OF BATAM)

Agromet ◽  
2005 ◽  
Vol 19 (2) ◽  
pp. 57
Author(s):  
Z. Noor ◽  
B.F. Simatupang ◽  
Yonny Koesmaryono
Keyword(s):  
New Zealand ◽  
Solar Radiation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Radiation Intensity ◽  
Ultra Violet ◽  
Sweet Pepper ◽  
Area Index ◽  
Hydroponic System ◽  
Solar Radiation Intensity

<p>An experiment has been conducted in Batam Island to study the response of sweet pepper which cultivated at lowland of 20 m asl, during November 2001 to May 2002. Five varieties have been used namely, Bangkok, Gold Flame, New Zealand, Spartacus and Tropica. Plants cultivated using hydroponic system under plastic house with ultra violet protection. The radiation of 100% (control) and it reduce of 25% and 50% used as treatment in order to determine the microclimate favourable for growing pepper in lowland. The results shown that reducing radiation intensity has influenced significantly on vegetatif growth, except leaf area index. The plants were grown under 100% and 25% radiation intensity performed taller with more branches compare to the plants under 50%. Variety of Spartacus has grew tallest than others. Stem diameter of control plants performed bigger than other plants, while reducing radiation intensity has no effect significantly to leaf area index. Experiment also revealed that reducing radiation intensity has significant effect on number and weight of peppers per plant, and thickness of flesh, compare to control. In general, Gold flame has produced best quality than others varieties although it has less number of fruits compare to Tropica.</p>

Fast determination of light availability and leaf area index in tropical forests

2002 ◽  
Vol 18 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Laurent Cournac ◽  
Marc-Antoine Dubois ◽  
Jérôme Chave ◽  
Bernard Riéra
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Optical Sensors ◽  
Light Availability ◽  
Tree Height ◽  
Light Transmittance ◽  
Limiting Factor ◽  
Area Index ◽  
Gap Fraction ◽  
Direct Measurements

An important property of plant communities is the Leaf Area Index (LAI), which is the vertically integrated surface of leaves per unit of ground area. Leaves are the primary sites of photosynthesis and transpiration, thus the LAI, which conditions the light interception by the canopy, is directly related to carbon and water exchange with the atmosphere at the stand scale (McNaughton & Jarvis 1983). LAI also has an impact on tree growth through the interception of light. Light availability below canopies is the principal limiting factor of tree recruitment and growth in forests (Denslow et al. 1990). Several methodologies have been used for measuring LAI in the field. These can be classiffed in four categories (Marshall & Waring 1986): (1) direct measurements by litterfall collection or destructive sampling, (2) allometric correlations with variables such as tree height or tree diameter, (3) gap-fraction assessment (e.g. with hemispherical photographs), (4) measurement of light transmittance with optical sensors.

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