Red pine in mixed stands?

Last week I went downeast with Kyle Burdick to do the Fourth Machias Lake-Gasabias Lake- Nicatous Lake route. We never found the Gasabias Portage, which was a pain, but we saw some beautiful pine forests on Fourth Machias and Nicatous. White and red pine play a more dominant role here than northern Maine; if you never leave the lakes you might think pine was all that grew here. I think this goes hand in hand with the greater place of fire downeast than anywhere up north. Unfortunately, Hancock and Washington Counties are not included in the early survey records, so it is hard to demonstrate fire's historic place here. (But if anyone could ever find the surveys from Bingham's Penobscot Purchase, that would be a goldmine. For that matter, the surveys from his Kennebec Purchase would tell us a lot about pre-settlement forests in western Maine.)

Most of the red pine on the lakes is in fairly pure, even-aged clumps, as you'd expect from fire origin. But there are a fair number of mixed pine-hemlock-spruce stands, where red pine is sprinkled fairly thinly throughout. They don't look like older residuals, I think they are in the same cohort(s) as the spruce and hemlock. So how did these stands develop? Either they are fire-generated (unlikely, I think) or red pine is adapted to typical Acadian forest gap dynamics. It would be very interesting to take a closer look at red pine in mixed stands, and understand its potential recruitment pathways better. I suspect that on pine-friendly outwash sites (i.e. near Nicatous), red pine can regenerate after small partial disturbances. The picture shows some nice red pine seedlings coming up in a light (trails-only) cut near the lake. 

Structural Complexity Enhancement

I was in Vermont for two days visiting Bill Keeton and Yurij Bihun to discuss my Fulbright project, and had the chance to visit Bill's Structural Complexity Enhancement (SCE) plots in the Mt. Mansfield State Forest. Bill developed this harvest method as a means of speeding the development of late-successional features in maturing stands. It uses variable density thinning to make small gaps, release midstory trees, and open up the crowns of canopy dominants, all while retaining the largest stems. Snags and CWD are deliberately 

created, and in some treatments trees are even pushed over to simulate windthow.

In adjacent plots there are traditional single-tree and group selection treatments, but with the residual

 basal area increased from normal and the max. diameter increased to 24 inches. This is meant to demonstrate how simply tweaking traditional harvest systems might enhance structural complexity, in comparison to the SCE method. 

I have to say, even the traditional treatments have some pretty impressive "big structure" (see right), but the vertical and horizontal diversity is noticeably lower. The SCE treatment is a jumble of small gaps, poletimber, snags and big canopy trees, arranged with none of the order and uniformity of selection. This is the point, and it is impressively "complex". Happily, Bill has found that sugar maple will regenerate in the tiny gaps created (and yellow birch will on the artificial tip-up mounds). Also, SCE actually benefits populations of late-successional herbs (they don't get overwhelmed by ruderals) and has boosted red-backed salamander populations due to more CWD. 

It is nice to see a couple of concrete biodiversity benefits from SCE. I have certainly seen how important old, complex stands can be for rare lichens. But the number of species that are actually dependent on such stands seems pretty low. For SCE and similar treatments to catch on, I think we would have to see how structural complexity benefits non-obligate species. Does it allow a greater breadth of successional guilds to use a stand at the same time? Could we effectively "pack in" more habitat value per stand by creating more structural diversity and more niches? 

Microburst, July 2006

In July 2006, we had an amazing microburst 

windstorm come through our region. I don't know its exact trajectory, but I think it blew SW-NE, hitting Somerville,

 Palermo and Liberty especially hard. I heard that some southern Kennebec County towns also got hit, and there is impressive windthrow from about the same time on some islands in Casco Bay. 

When this storm occurred we had not had a serious large-scale disturbance in Somerville since the Ice Storm of 1998. The microburst created gaps in the canopy from single-tree size to 5+ acres. The arrangement of snags, downed logs and residual trees after the event was fascinating: a textbook example of how natural disturbance impacts stand development. Certain species were hit harder than others. Tall, emergent white pines were "combed out" of mixed forests. Pure, old-field pine stands (including some that I helped my friend Shaun to thin immaculately) were totalled, often through snapping.  On mixed hardwood-hemlock ridges, aspen tended to be the hardest hit, while red oak and red maple were thrown selectively. A lot of hardwoods sustained heavy crown damage but didn't fall. I have read that yellow birch and red maple are adapted to slough off large branches in wind storms to reduce their crown "sail".

Where winds were strong enough, the storm did amazing damage to pure stands of oak sawtimber, which I had thought of as a wind-resistant species. 

Hemlock was pretty susceptible, especially if it was already decadent. In Casco Bay (Whaleboat Island) the storms knocked down swathes of red spruce about 200 feet wide, while leaving adjacent areas untouched. But even within areas of susceptible species like spruce, there were still lots of "canopy legacies"- snags, heavily-damaged trees and surprisingly intact survivors.

One thing that really fascinated me was how well this storm replicated, on a much smaller scale, what I have read about the Hurricane of 1938. Just as in 1937, in 2005 there was a large supply of dense old-field pine stands in stem exclusion. These were growing on abandoned farmland, on sites where such a structure and composition was probably unnatural. The storm knocked them down almost without exception. After the blowdown and resultant salvage, the advance regeneration of oak, maple and ash is dominating the site. I suspect that many of the mixed hardwood stands in Somerville had a similar origin.

Of course, salvage has really changed the development trajectory for these areas. In Somerville and Palermo, almost the entire affected are was salvaged. (Often quite well). Where there was a lot of wood on the ground, salvage tended to destroy most of the advance regeneration. I think that the best place to see how storm-affected stands develop without salvage will be Whaleboat Island, which is owned by TNC as a coastal reserve. 

Welcome to my blog!

Hello!

     I was recently going through my huge collection of pictures I have taken in the woods, and decided that I should really share these with fellow forestry wonks. I also wanted a place to talk about my work and the ideas in forestry that really interest me, and to hear what other people think. I won't be using this blog for general, non-forestry related things in my life. So if you're not looking for silvicultural ramblings and lots of pictures of trees, turn back now! 

     

If that kind of thing gets you going, than I hope you'll enjoy my future posts. Please respond frequently- I will put a lot of questions in here that I hope people will help answer. I'm going to start with some of my favorite pics and topics from the last couple years. In a couple months I should start posting on my exciting new work in Ukraine. 

     Enjoy!