[Nectar productivity of Tilia amurensis in a broadleaved-conifer mixed forest in Changbai Mountains, China].

Tilia amurensis is one of (co-)dominant species in the broadleaved-conifer mixed forest in Northeast China, with high commercial and nectariferous values. We estimated the quantity of nectar secretion from individual trees to population or stand levels based on observation and statistical analysis. An equation for individual-tree nectar secretion was established, which was used to estimate nectar quantity at the stand level. We analyzed the relationships between nectar secretion and basal area or stem volume. The booming time for single flower was in average 6-8 days, with a nectar secretion period of about five days. The quantity for the entire period was estimated at 8.58 mg per flower. Sugar contents in the nectar, average 37.7%, showed diurnal variations, being high in the mid-noon and low in the early morning and late afternoon. The average diameter (DBH) of the species was approximately 40 cm, which was estimated to possess as much as 18×10 4 single flowers and 1.56 kg (or pure sugar 0.588 kg) of nectar. At the stand level, the nectar production potential was 79-147 kg (or 0.0686-0.1285 m 3 , pure sugar 29.78-55.42 kg) per hectare. There was a close correlation between nectar quantity and basal area or timber volume at both individual and stand levels, which could be used to estimate the nectar quantity for macro-scale forest area based on inventory data.