Rookie Questions - Trees not doing so hot...

[gmac17]

We have a cottage in Quebec and I've noticed that in recent years more and more trees are dying or just looking less healthy. The trees are on an island in the middle of a lake, and there isn't a lot of soil there - very sandy. I'm not sure if the trees are just getting old, are diseased or something else. (this year in particular the caterpillars are very bad, not sure if that is related at all).

We have never "cared for" the trees beyond cutting them down when they die. The trees are pretty much pine, poplar and birch. As you can see from the pics, the pines have tons of dead branches - should we trim these?

Many of the taller poplars have only a few branches with any leaves. There are a good number of young trees growing, but it will take them forever to get as tall as the existing trees (we transplanted some 18" pines 10 years ago and now they are only about 5' tall).

Any suggestions, things to look out for etc. would be much appreciated - I'm really worried that in 10 years it will look like a completely different place.

the "attach photos" doesn't seem to be working so here is a link to some pics:

http://treepics.eboard.com
thanks,

gmac

 

[Sprig]

I hate to say it but if there isn't obvious bug damage it could very well be acid rain, just look to the north and you'll see a huge defoliated landscape, no fish,poisoned lakes, millions of acres of dead/denuded trees. The landscape in some northern reaches is very, very changed. It has gotten worse since the Kyoto agreement because we've been trading off 'pollution points' or whatever the fk they call them and our industries have kept on getting worse.
If this is the potential problem you may save some trees by balancing the soil around them again so that the roots aren't killed. Just my 0.02$ worth based on the pics but I think something to consider.

 

[gmac17]

That is a possibility, though the trees on the mainland seem healthy. I will look into this further though.

In general should you trim dead branches on those pines?