Yellowstone: why all those fallen trees ?
 

We have been very impressed for the beauty of the scenery and wildlife at YNP but were also impressed for the huge number, hundreds of thousands of fallen trees throughout the entire park !! We have asked the reason for that but got different answers: some said becuse of the great fire in 1988, others said that the inner volcanic activity affects the soil which let then trees die, others said both reasons are valid. We are still a bit confused. Does anyone have specific and detailled information ? Those fallen trees were not burnt but just with their original size, grey colour and just fallen down.. !!
The positive is that new young forest is growing up over there !!

thank you !!
fabio

We were in Yellowstone about 7-8 years ago and the Rangers explained that the downed trees were the result of 'blowdowns'. This is caused by extreme winds and happens every once in awhile. This may be only one of several possible explanations but seemed true since the trees at that time did not have any fire damage.

There are several reasons you see all that down timber. Yes, the great fires were part of it, yes some are blowdowns, and some are from natural overcrowding and self-thinning. The main reason you see all the down trees is the altitude and dry air. In most places the trees would have rotted away in a few years but in the Yellowstone country they last for years, many years in some instances. You are seeing the results of decades instead of just a few years accumulation.

The answer is so multi faceted that it defies a simple explanation.
If you are in a new growth area and see a large number of downed tree trunks and a few dead trees still standing, there is a good chance that you are in a burn area.

Otherwise, the natural attrition rate from pathogens, parasites like beetles, the preservation conditions, the blowdowns from wind, old age decay, etc. would explain a large number of them.

The Park Service does not clear timber unless the tree is blocking a road or lying across a picnic table, is causing a problem in the lodging areas or contaminating a thermal feature.

Usually there are not many trees in the thermal areas because the ph of the soil does not permit tree growth.

Some trees grow close to a few geysers, like Lone Star and Castle, but rarely does one fall into the geyser itself. Old Faithful itself sits in a very barren area.
If I recall correctly, trees are close enough to Castle that one can sit in the shade and wait for an eruption.

I have noticed the same conditions in Yellowstone. I got many answers like you did. Finally a professor of forestry gave me the most complex answer, and it got ahead of me rather quickly.

Let's just say that there are oodles of reasons. Preservation conditions and limited removal of down timber are two reasons why dead trees accumulate. Once they die, nothing takes them away very quickly.

Some were blowdowns as mentioned but there are many areas of down trees a result of the fires of 88. The trees died standing up with little damage to the upper part of the tree, the roots are now rotten and the trees have fallen due to weather, wind and snow.. The young trees are taking over. We have visited the Park well over a dozen times, some prior to the fires of 88 and some after. It is wonderful to see nature heal the wounds.

wow !! thanks to all of you !

all these different reasons make this place even more special and wonderful !

I just read an article about an infestation of a particular type of beetle that is killing off lots of trees in the west. I wonder if it is due to that?

Those beetles have always killed a few trees but most trees are able to defend against them and survive. The current infestations are much more pronounced. I've seen entire mountainsides turn brown as nearly all the trees were killed by the beetle. If this were the main cause in Yellowstone, you would see acres of dead trees.

This same "beetle" is doing alot of damage in the Tahoe Basin along with the polution caused by "overuse"-(cars and people)

rm_mn

We have just seen acres of dead trees in Yellowstone !!!

and also a lot of entire mountainsides of dead trees !