Estimating defoliation in boreal coniferous forests by combining Landsat TM, aerial photographs and field data

Heikkilä, Juho; Nevalainen, Seppo; Tokola, Timo

doi:10.1016/s0378-1127(00)00671-x

Cited by 15 publications

(8 citation statements)

References 27 publications

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“…The estimated age (number of rings counted in wood samples taken at 1.3 m) of sampled trees ranged from 25 to 33 years. The ICP (International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests) monitoring methodology was used for the visual assessment of crown density and transparency (UN/ECE 1994) since it has been used in similar decline studies in Europe (see for example Heikkilä et al 2002). Percent crown defoliation was assessed visually by the first author because estimates of defoliation vary among observers.…”

Section: Field Samplingmentioning

confidence: 99%

Selective drought-induced decline of pine species in southeastern Spain

et al. 2012

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The negative impacts of severe drought on the growth and vigor of tree species and their relationship with forest decline have not been properly evaluated taking into account the differential responses to such stress of trees, sites and species. We evaluated these responses by quantifying the changes in radial growth of plantations of four pine species (Pinus sylvestris, Pinus nigra, Pinus pinaster, Pinus halepensis) which showed distinct decline and defoliation levels in southeastern Spain. We used dendrochronological methods, defoliation records, linear mixed models of basal area increment and dynamic factor analysis to quantify the responses of trees at the species and individual scales to site conditions and drought stress. In the region a temperature rise and a decrease in spring precipitation have led to drier conditions during the late twentieth century characterized by severe droughts in the 1990s and 2000s. As expected, the defoliation levels and the reductions in basal area increment were higher in those species more vulnerable to drought-induced xylem embolism (P. sylvestris) than in those more resistant (P. halepensis). Species adapted to xeric conditions but with high growth rates, such as P. pinaster, were also vulnerable to drought-induced decline. The reduction in basal area increment and the Climatic Change (2012) 113:767-785 defoliation events occurred after consecutive severe droughts. A decrease in spring precipitation, which is the main driver of radial growth, is the most plausible cause of recent forest decline. The sharp growth reduction and widespread defoliation of the most affected pine plantations of Scots pine make their future persistence in drought-prone sites unlikely under the forecasted warmer and drier conditions.

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Section: Field Samplingmentioning

confidence: 99%

Selective drought-induced decline of pine species in southeastern Spain

et al. 2012

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“…Sampled stands in those grids with multiple stands were randomly selected. For each tree measurements and observations were made of physiographic variables (elevation, slope and aspect), size (dbh, height and crown height), age (number of rings at 1.3 m) and crown damage (percentage of defoliation) using a semi-quantitative scale based on the percentage of crown defoliation (Mueller and Stierlin, 1990) (Table 2) and the ICP (International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests) monitoring methodology (UN/ECE, 1994) since it has been used in similar decline studies in Europe (see for example Heikkilä et al, 2002). Percent crown defoliation (as proxy indicator of damage) was assessed visually by the first author because estimates of defoliation vary among observers.…”

Section: Field Procedures and Tree Ring Analysismentioning

confidence: 99%

Is drought the main decline factor at the rear edge of Europe? The case of southern Iberian pine plantations

Sánchez‐Salguero

Navarro-Cerrillo

Swetnam

et al. 2012

Forest Ecology and Management

103

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“…In Germany, five pest species (orders Lepidoptera and Hymenoptera) are common in Scots pine plantations. They are often referred to as grand pine defoliators because of their repetitive mass outbreaks (Majunke et al 2004) Several studies considering a variety of sensors and methods have suggested the capabilities of optical satellite remote sensing for defoliation mapping (Radeloff et al 1999, Heikkilä et al 2002, Sims et al 2007, De Beurs & Townsend 2008, Chávez & Clevers 2012, Thayn 2013, Adelabu et al 2014, Sangüesa-Barreda et al 2014. To understand how satellite remote sensing can be used to detect or assess defoliation, it is important to review the interaction of light and vegetation in general, and the forest canopy in specific.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity analysis of RapidEye spectral bands and derived vegetation indices for insect defoliation detection in pure Scots pine stands

Marx¹,

Kleinschmit²

2017

iForest

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This study investigated the statistical relationship between defoliation in pine forests infested by nun moths (Lymantria monacha) and the spectral bands of the RapidEye sensor, including the derived normalized difference vegetation index (NDVI) and the normalized difference red-edge index (NDRE). The strength of the relationship between the spectral variables and the ground reference samples of percent remaining foliage (PRF) was assessed over three test years by the Spearman's ρ correlation coefficient, revealing the following ranking order (from high to low ρ): NDRE, NDVI, red, NIR, green, blue, and rededge. A special focus was directed at the vegetation indices. In both discriminant analyses and decision tree classification, the NDRE yielded higher classification accuracy in the defoliation classes containing none to moderate levels of defoliation, whereas the NDVI yielded higher classification accuracy in the defoliation classes representing severe or complete defoliation. We concluded that the NDRE and the NDVI respond very similarly to changes in the amount of foliage, but exhibit particular strengths at different defoliation levels. Combining the NDRE and the NDVI in one discriminant function, the average gain of overall accuracy amounted to 7.8 percentage points compared to the NDRE only, and 7.4 percentage points compared to the NDVI only. Using both vegetation indices in a machine-learning-based decision tree classifier, the overall accuracy further improved and reached 81% for the test year 2012, 71% for 2013, and 79% for the test year 2014.

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Estimating defoliation in boreal coniferous forests by combining Landsat TM, aerial photographs and field data

Cited by 15 publications

References 27 publications

Selective drought-induced decline of pine species in southeastern Spain

Selective drought-induced decline of pine species in southeastern Spain

Is drought the main decline factor at the rear edge of Europe? The case of southern Iberian pine plantations

Sensitivity analysis of RapidEye spectral bands and derived vegetation indices for insect defoliation detection in pure Scots pine stands

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