Do you remember how wet it was last summer, and how we were all wondering about the affect of the rain on the forest? (If not, refresh your memory with this 2009 blog, where we ponder the unusually high number of how-to-build-an-arc story queries).
In at least one case, our questions have been answered.
Many readers have contacted us in the last few weeks to ask about white pine needle damage. Around here, many white pines looked, in late May, like Tamaracks in November; as I write this, brown, dead needles are blowing off the trees around the office, leaving them looking pretty thin and scrawny.
Turns out the above average precipitation we had in May and June of 2009 is playing a role in the brown needles we’re observing in 2010. In Vermont, the Vermont Department of Forests, Parks, and Recreation reports that at least two different needlecast diseases have been identified on symptomatic pines. One is the Brown Spot Needle Blight, caused by Scirrhia acicola. The other is white pine needlecast, caused by Canavirgella banfieldii. Both of these fungal diseases were enabled by last spring’s wet weather, when ideal conditions allowed fungal spores to infect the interior needles of the trees.
Of course scientists, being scientists, are never content to blame any malady on just one source. Many suspect that the late frosts we had this spring – frosts that in most areas are going down as the worst on record – have also played a role in the needle damage. The early warmth, followed by the record cold, combined with the fungus, created a perfect storm. Oh, and by the way, the pine leaf adelgid – an insect pest – has also been reported as being more common than usual in certain areas.
Similar white pine needle damage has been reported throughout our readership area. The majority of calls to the Maine Forest Service this week involved questions about shedding white pines. The New Hampshire Division of Forest & Lands reports that on many sites, fungal outbreaks have been bad for the past three years, which makes this year’s dramatic damage troubling.
The bottom line is that if your brown pines are growing on a good site, and they’re otherwise healthy, they should be fine. They will shed their dead needles but their new shoots should grow normally. Mortality on lower branches may accelerate, but by July, the trees should be green, even while they look thinner than normal.
If the needles on your new shoots are still brown in July, you don’t have healthy trees. Foresters indicate that it’s certainly possible that this event could cause mortality among the weaker trees in a stand.
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