Hello Foresters and Botanists working in the Sal (Shorea robusta) forest: I am wondering about natural tree fall in sal forests. I observed very large gaps in sal forest caused by fall of mature Sal trees. In a quiet day, I observed fall of a standing tree, which looked healthy. Other people reported several cases of such kind. I doubt the if the tree fall is associated with the occasional swampyness of the forest floor. Larger gaps in the protected forest may be associated with abrupt fall of trees. Any idea about the phenomenon?
Its may be due to SAL heartwood borer Hoplocerambyx spinicornis. It is epidemic...Please have a look at the following link
http://www.fao.org/docrep/ARTICLE/WFC/XII/0739-B1.HTM
Yes such situation is very much common in Sal (Shorea robusta) forest, but such falling is common manly in mature tree stand, not in young tree or pole. Also, if you look to the stem it looks like a humepipe. Though no specific cause is reported yet, I think, it might be due to heartwood borer (as said by Sreejith Ashtomoorthy) or maybe some age-related phenomenon or root affecting organism or maybe all. So, more research is needed in this field.
Dear Sreejit and Rajeev,
Thank you very much for response. Yes it could be borer as suggested by Sreehith. yes, I also doubt some phenomenon related to root decay as suggested by Rajeev. I will explore these in my next visit to the sites.
Rrakash ji, thank you for response and the articles. But the first one (review) doesnot look credible as they have even failed to identify Sal itself.
I have seen this in Madhupur National park, Tangail Forest Division, Bangladesh. The reason was the trees are coming from coppices that not have a strong anchorage with main tap roots!
during your visit you may also collect data on fire frequency because fire promotes the attack of shoot borer. In addition you may also note down the the girth/age class of effected trees since borer mainly concentrate on certain age classes. best luck
Thank you very much for suggestions Sreejith ji. , sure, I will do it.