It’s very wet on Prince of Wales Island.
Yellow-cedar, a prominent tree species along the coastal margin (ranging from California to Alaska) is dying, in some places rapidly.
About 8% of the current range is currently affected, and in places where the mortality hits, generally about 70% of the basal area dies. Basal area is a measure of how much area the trunks (stems) cover near the ground. This mortality is directly related to a warming climate, as it is related to low snow coverage and subsequent root freezing in cold snaps.
There’s a variety of efforts focused on this decline – where it’s happening, how fast, where it’s going, and what’s coming back. There has been quite a bit of good work on the causes of the decline, but very little information is out there as to the consequences.
Two of those studies brought us to Prince of Wales, in late September, in a rainstorm. One aspect of the decline is social – what are logging outfits going to do with this change? The Alaska Coastal Rainforest Center and UAS are running a study for foresters to experiment with harvesting dead yellow-cedar instead of live. Logging of dead trees (unfortunately termed “salvage,” though dead trees are an important part of the ecosystem as well as live trees) is a means to retain live cedar in areas they might survive. Hence the second study – following the effects of the decline and harvest.
As part of this effort we went to POW pre-sale, measuring and tagging all trees, seedlings, saplings, and counting the coverage of various ground cover species. If something changes, we’ll know. Importantly, we’ll know if the logging causes changes in successional trajectories – if we will get different forests as a result. One part of this is an experiment, planting redcedar (Thuja plicata) in areas where yellow-cedar is dying. Redcedar is a similar tree ecologically; where it lives, how it competes, etc. But it’s not so susceptible to freezing damage. There may be a way to preserve ecological functions and maintain the forest via this sort of adaptive management.
The sites on northern Prince of Wales are right on the redcedar range edge, and we found redcedar naturally moving into the plots already, perhaps following the decline. It’s hard to say for sure at this time, but they were all young and healthy, under a canopy of (mostly) dead yellow-cedar, and just uphill from mature redcedar. Natural migration assisted by disturbance?
So, in the pouring rain, and completely soaked, we counted thousands of big trees, little trees, trees trees trees, noting damage, health, where they were growing, understory species, and a variety of other indicators. So next time you’re on north Prince of Wales, look around for the red and yellow cedars and you might be seeing a slow moving – but moving! – edge of an entire species.
Participants – Allison Bidlack, Sarah Bisbing, John Krapek, Katherine Benedict, and Brian Buma
Contact: Brian Buma, firstname.lastname@example.org