Relative absorptance of intact branches measured with an integrating sphere was compared to leaf area estimated by conventional methods (volume displacement and scanning area meter) for three conifer species: Picea mariana (Mill.) BSP, Pinus banksiana (Lamb.) and Pseudotsuga menziesii (Mirb.) Franco. A consistent relationship between relative absorptance and surface area emerged for the three s...

Leaf longevity determines the annual cost of replacing foliage biomass and influences water and nutrient budgets. Longevity is readily estimated in most evergreen species by annual bud scars along the shoot. However, some species with indeterminate growth do not show these annual markers, making estimation of longevity difficult. One of these species is the widespread and economically valuable ...

Leaf area index (LAI) can be measured either directly, using destructive methods, or indirectly using optical methods that are based on the tight relationship between LAI and canopy light transmittance. Third, innovative approach for LAI measuring is usage of remote sensing data, especially airborne laser scanning (ALS) data shows itself as a advisable source for purposes of LAI modelling in la...

A numnber of authors have recommended the use of photometric apparatus for determining leaf area, and at least 1 commercially-manufactured instrument is available. In principle the leaf is placed between a light source and a photocell or battery of photocells: the reduction in photocell output due to the presence of the leaf then gives a measure of leaf area. The transmission of light through t...

Fuel moisture content (FMC) is used in forest fire danger models to characterise the moisture status of the foliage. FMC expresses the amount of water in a leaf relative to the amount of dry matter and differs from measures of leaf water content which express the amount of water in a leaf relative to its area. FMC is related to both leaf water content and leaf dry matter content, and the relati...

Crop biomass is a critical variable for characterizing crop growth development, understanding dry matter partitioning, and predicting grain yield. Previous studies on the spectroscopic estimation of crop biomass focused on the use of various spectral indices based on chlorophyll absorption features and found that they often became saturated at high biomass levels. Given that crop biomass is com...

This study was conducted to evaluate the response of Iranian promisinglate blooming almond genotypes to deficit-irrigation stress on GN15 rootstock. One-year old plants subjectedto three deficit-irrigation, including moderate and severe stress (soil water potential, Ψsoil = -0.8 and -1.6 MPa, respectively) and a control treatment (Ψsoil= -0.33 MPa), were applied for six weeks to five grafting c...

The segmentation of individual leaves in plant images is still a challenging task, especially in case of leaf overlaps. The exact determination of individual leaf areas could improve the biomass estimation which is a good indicator for plant performance. In addition, the number of leaves is directly related to plant development, leaf counts give insight into changing plant development stages. M...

Estimating plant traits in herbaceous plant assemblages from spectral reflectance data requires aggregation of small scale trait variations to a canopy mean value that is ecologically meaningful and corresponds to the trait content that affects the canopy spectral signal. We investigated estimation capacities of plant traits in a herbaceous setting and how different trait-aggregation methods in...