Foliation of spruce in the Giant Mts. and its coherence with growth and climate over the last 100 years

Abstract

Five spruces (Picea abies [L.] Karst.) in the Giant Mts., Czech Republic were investigated to reconstruct variations in their foliation over the last 100 years and to establish possible coherences with growth and climate. Foliation was assessed by means of the needle traces in the main trunk. The annual average needle production of 355 needles per shoot correlated with the annual shoot length and was affected by the temperature prevailing in March and October of the previous year. A determination of needle production by the length of the vegetation period is discussed. The needle retention of the trees was 6.5 needle sets on average but there were considerable long-term variations, and maximum needle age even reached 9.8 years. Needle shed was between 0.1 and 2.3 needle sets per year and no connection was revealed between needle shed and radial increment or shoot growth. Needle retention and annual needle shed were independent of climate.