Estimating crown defoliation and chemical constituents in the needles of Scots pine (Pinus sylvestris L.) trees by means of in-situ acquired hyperspectral data

Abstract

The most successful studies in forest health assessment are those which involve using the potential of imaging spectrometry and concentrating on measuring of the spectral reflectance beyond the ability of human vision. Thus, we consider the hyperspectral imaging as a technique having a great potential for forest health assessment. This study is dealing with the estimation of crown defoliation and concentrations of some chemical constituents in the needles of Scots pine (Pinus sylvestris L.) trees by means of in-situ acquired hyperspectral data. Needle samples from 73 Scots pine trees having crown defoliation in the range from 5% to 80% (using 5% gradation) were collected in two mature stands located in eastern Lithuania. The concentrations of ten chemical elements in the needles were also measured. The hyperspectral reflectance data of the needles samples was recorded under laboratory conditions using Themis Vision Systems VNIR 400H portable scanning hyperspectral imaging camera operating in the 400-1000 nm range