Tree growth variability in Pinus nigra plantations modulated by climate and soil properties

To understand and manage Mediterranean forested ecosystems under a changing climate, forest managers require improved knowledge of forest plantations ability to adaptat to drought stress. This paper analyses the radial growth dynamics (earlywood width, EW; latewood width, LW; tree-ring width, TRW; basal area increment, BAI) and vegetation activity (normalized difference vegetation index, NDVI; enhanced vegetation index, EVI) of Pinus nigra plantations growing on two sites (lower, upper) with contrasting edaphic conditions, in eastern Albania, and evaluates the growth responses to climate (temperature and precipitation) and drought (standardized precipitation index, SPI; standardized precipitation evaporation index, SPEI). P. nigra plantations showed pronounced differences in growth and response to climate (drought) and soil variations between sites. Trees at the lower site, located on poor soils, showed lower growth rates and higher response to June-July precipitation, August temperatures and drought index SPI (< 8 months) in summer as compared to trees at the upper site distributed on rich soils which remained more buffered. At the upper site, the high vegetation activity in July (EVI) and August (NDVI) affected considerably the radial growth rate, whereas at the lower site, only July EVI showed significant relationship with EW, LW and TRW. Vegetation indices at the lower site showed the strongest association with drought. We conclude that future management of P. nigra plantations should be properly adapted to modulate variations in climate and to sustain tree growth and productivity, triggered by local site conditions.