I have done a little research on terpenes in pine needles and I'll give you a list of the effects of terpenes on soil:
-Monoterpenes might alter rates of nutrient cycling inhibiting nitrification in the forest soil
-In general, decomposition of secondary compounds in leaf litter is rather a slow process compared to primary metabolites (terpenes are secondary metabolites)
-Monoterpenes can be present in nearly equal concentrations in recently fallen leaf litter comapred to green needles (this quote is in conjunction with some data that eluded to the fact that resin acids and phenolic compounds retard degredation of carbon compounds more than terpenes and terpenoids)
-Monoterpenes are slightly volatile compounds and will most likely exit leaf litter via volatisation of by leaching
Furthermore, any deterrence to decomposition from monoterpenes would be short lived (say a little over a year) due to the fact that after 12 months in a Scotts Pine forest most terpenes were absent from the soil
Anyway, I have more information on monoterpenes and their effects on decomposition but, a little note on resin acids (found in pine needles):
Resin Acids have an important role in inhibiting the growth of wood rotting fungi because of their toxic effects and resin impregnation may act as nontoixc waterproofing layer that prevents fungal penetration and growth.
Anyway, these effects of Resin acids could play a role in the germination of seeds as well.
Last edited by opabinia51
on Mon Apr 03, 2006 3:15 am, edited 1 time in total.