LITTERFALL, LITTER TURNOVER AND SOIL RESPIRATION IN TWO PINE FOREST PLANTATIONS IN CENTRAL JAVA, INDONESIA

Abstract

Litterfall, litter turnover and soil respiration were studied for one year in two forest plantations ofPinus merkusii, one on the slopes of Mount Merapi (at 800m) and another on the slopes of Mount Merbabu (at 1050m) in Central Java. The dominant component of total litterfall differed per site. At the Merapi site total litterfall was 9 t ha^-1 y ^{- 1} , nearly 60% of which consisted of female cones. At the Merbabu site total litterfall was 4 t ha^-1 y^-1 and needles were the dominant component (63%). At the Merapi site, litter turnover during the dry season (Kd=0.08) was four times that in the wet season (k_w = 0.20). Because of litter removal by the local people at Merbabu, derived litter turnover values were not realistic. The removal also decreased litter standing crop and significantly reduced the CO, efflux from the litter and soil (0.19 - 0.35 g m^-2 h^-1). The CO₂ production at Merapi was 0.37- 0.45 g m^-2 h^-1. There was no relationship between CO₂ production and rainfall at Merapi because moisture was not limiting to the mulch effect of the litter standing crop. At Merbabu, where the water content of the litter reached very low values by the end of the dry season (7.2%), there was a positive relationship between CO₂ production and rainfall.