Tuesday, November 17, 2009

Tree quiz #1

I saw this tree in the woods in Northboro. What kind of tree is it?
How do you know? What is unusual about that? What is that feature an
adaptation to?


  1. Hey, I just learned about this in Community Ecology a few weeks ago! I believe that's a pitch pine. It's extremely fire-adapted, and has epicormic buds on the trunk which are normally suppressed but can sprout if its limbs are killed in a fire. Pitch pines are usually on very dry, fire-prone sites... where in Northboro was this? It looks out of place... is are those black birches and a red oak surrounding it?

  2. Yep, that's what I thought.

    The unusual thing about this, for those who don't know, is that this is the only conifer that can sprout like this.

    Vivian, can it stump sprout if cut down to a small stump, they way deciduous trees do? I guess that depends on whether it has epicormic buds all the way down the trunk? Again, for those who don't know, conifers generally don't stump sprout.

    I had the same question about the site. I had thought it grows on only dry, sandy sites. The site was upland but didn't look all that dry or sandy to me. Yes, there were black birches and red oaks around it. This is suprising too, as it is often in association with scrub oak.

    There was a small grove of those pitch pines in that area, all about the same age. If it was never a fire prone site, would someone have planted pitch pine there for some reason in the past?

    Even if it used to be a fire prone site, I didn't see any young ones coming up, consistent with fire suppression.

    Maybe it used to be fire prone, and with fire suppression, whatever scrub oak used to be there has been out competed by other species. Looks like the pitch pine will go the same way.

  3. Forgot to answer where in Northboro this was. It was in the Mt Pisgah conservation area.

  4. This was the dominant tree where I grew up on the Cape. The only other trees around my house were scrub oaks and an occasional red oak. I don't think they can stump-sprout. I never saw one do it but I did see a lot of pitch pine stumps as hurricanes took their toll. Other than on community ecology field trips (same class as Vivian but a different section), I have seen them lately in Sherborn and around Lake Waban in Wellesley. Just one or two trees at a time and in places that seemed too wet. No sign of recruitment. I also wondered how they got there.

  5. Yep, I believe the pitch pine is the only conifer that can stump-sprout.

    Throughout the course, we have had to write observation papers that describe two different plant communities and figure out why they are different. This sounds like a perfect site for my last paper! Do you remember what trail it was on?

  6. Hi Dan! Hmm, my notes from our airport field trip say that the pitch pine is the only stump-sprouting conifer...

    I did a quick search and it appears that their ability to stump-sprout may depend on their age:


  7. Hey Vivian - I can probably give you GPS coordinates!! I had my GPS on during that hike, so I can use Dan F's nifty software to get coords. It might take me a few days, though, since Tech Support is away on a business trip.

    As for stump sprouting, I wonder if it also depends on exactly how close to ground level it is cut. Those buds might not go all the way down. I haven't seen too many of these trees, but what I've noticed so far is that the buds become sparser as you go closer to the ground. That seemed to be the case on this particular tree, too. I have another photo of the lower part of th trunk which I can send you.

    Perhaps with age, the lower buds die?

  8. Stump sprouting in pitch pine: At www.fs.fed.us/database/feis/plants/tree/pinrig/all.html it says that stump sprouting does not occur from epicormic buds. (These do in fact become less numerous on the lower part of the trunk as the tree ages, by the way. A tree equivalent of a receding hair line, I guess.)

    Stump sprouts arise from basal sprouts on the root crown. However, if fire is suppressed, humus accumulates. A thick layer of humus eventually suppresses the basal buds and thus the ability of the tree to sprout from the stump. So, fire suppression probably explains why Dan never noticed stump sprouting on the Cape.

    Fire suppression might also explain why we are finding the occasional small stand of pitch pine in soil that does not appear poor and dry. That poor dry soil has been covered by the accumulated humus.

  9. Aha, thank you for that info! I asked about it in class today, and our teacher said that black birch and red oak are general enough in their site requirements that it's not necessarily weird to see them mixed in with pitch pine, especially on more ledgy sites. I'll have to see if I can figure that out when I go out there...

  10. Here is what I think re: the presence of black birch and red oak: (I have never taken that community ecology course, but am currently reading "Forest Ecosystems" by Perry et al -- a bit above me as I haven't the usual undergrad forestry prereq's but still illuminating)

    For pitch pine to persist as a climax species, repeated fire is necessary. It reproduces better with fire and likes the thin soil that persists with repeated burning. If fire is suppressed, pitch pine functions as an early seral species. Other species that reproduce well without fire and that like the accumulating humus, then invade and out compete the fire adapted trees. I think that is what is happening at Pisgah. The black birch, red oak, and others are replacing the pitch pine community.

    In fact, that is what is happening in many pitch pine - scrub oak communities throughout MA. I believe it is considered a rare (endangered?) habitat in MA.

    Sudbury Valley Trustees is trying to initiate efforts to restore the pitch pine - scrub oak community in Desert Natural Area in Marlboro/Sudbury. Restoration will require removal of the invading trees and then periodic, controlled burning to allow that fire adapted community to re-establish and persist.

    If you do check out that Pisgah site, look carefully for any young ones coming up. Their absence will be good evidence that the community is being replaced.