Is it really spring?

Since the equinox two weeks ago, we have had  one or two shirt-sleeve days that were almost painfully sunny.  I greeted familiar old trees as long-lost friends, solicitously inquiring after their health after the long, snowy winter.  

Nearly all fared well.  The small female red maple street tree I call Little Mama still has every one of the buds on three twigs I check periodically.  (I am trying to find out why so few buds form new branches; most of the buds must fail eventually, but not so far.)  

A big white pine on the other side of the block has suffered, though.  Two biggish limbs (butts of diameter 3 and 4 inches) fell some time during the winter.  I only spotted these a few days ago, but they may have been covered with snow before that.  More ominously is the browning of needles on several limbs: the browning begins at the tips and proceeds toward the bases.  A few minutes on the web brings up several possibilities, from salt damage to ozone damage.  The likeliest seems to be "winter burn," caused by dessication of the needles--especially since the damage is confined to a few limbs on the south (sunward) side of the tree.  I'm guessing this will go away in time. 

Four eastern hemlock trees not too far from the white pine all have browning needles on the lowest limbs.  I hope this is another case of winter burn: at least one of these trees was being attacked by wooly adelgids last season, but the damage seems too great to have been caused by the alien invasive insects that hide under the cottony white masses that mark the undersides of infected twigs. 

Today, April 2nd, I walked past long stretches of snow in 50+ degree sunshine, and wondered when we last had significant snow cover this late in the year.  I'm not talking about the snowplow Everests in the mall or school parking lots, or even the piles cleared from sidewalks and driveways, but snow that lies where it fell.  Especially in north-facing yards, undisturbed snow is often four to six inches deep. 

 Big red maple (Acer rubrum) of neighbor is bursting with flower buds.

 

Little Mama's buds are unscathed by nights below zero Fahrenheit and repeated snowfall.

 Big white pine with browing needles.

 Hemlocks infested with wooly adelgid also show winter damage.

A good deal of snow has disappeared just in the last few days: March 29, April 1, April 2.

 But there is still a lot of snow on the ground--not everywhere, but certainly in shaded sites.

In these yards, almost no shoveling has been done except for driveways.

 

 

A neighbor allows his single sugar maple to be tapped. 

The syrup from sap of several such trees has won prizes at local fairs.

I know--not native, but prettier than the native early-bloomer: skunk cabbage!

Eastern Hemlocks and the Threat of Woolly Adelgid

Full-grown.

Undersides of flat needles are striped.

Spring growth.

Young cones.

Mature cones.

From the spindly trees folks grow around here, and the way they crowd them and torture them into HEDGES, for all love, you'd never know that the eastern hemlock(Tsuga canadensis) is a majestic member of late-stage successional forest here in New England. 

I have been collecting locations of eastern hemlocks (Tsuga canadensis) on my neighborhood perambulations over the last month or so, and have a nice list of trees I look at regularly.  I was moved to do this less because of its iconic status--the third most prevalent tree in Vermont--than because of the danger eastern hemlock faces.  This tree is endangered by yet another of our many alien invasives: the woolly adelgid.  

Our local trees range from sad and tortured to moderately majestic.

 

 

Woolly adelgid (Adelges tsugae) was imported accidentally from Japan, and was first noticed in the US near Richmond, VA in the 1920s.  It is now affecting eastern hemlocks as far north as Massachusetts.  Woolly adelgid is an aphid-like "true bug" (insect order Hemiptera) that sucks the sap and starch from hemlock twigs, reducing their food stores.  This weakens the tree, allowing other insect, disease and drought stresses to overwhelm it.   

Wooly adelgid spreads short distances mainly by wind, and by birds and other animals the sticky egg sacks cling to.  Transport of infected nursery trees can spread the insects more widely.  

 

Each cottony mass tyically hides an individual and its several hundred eggs.

You will know you have this on your hemlock tree if you see the cottony egg masses on the undersides of twigs.  Affected trees will gradually lose needles, becoming more "transparent" and turning grayish.  Trees here in the north typically die four to ten years after infestation.  If allowed to expand unchecked, the woolly adelgid could doom so many of these beautiful trees that whole forest ecosystems could be irrevocably altered. 

Property owners can spray their smaller infested trees yearly with a non-toxic insecticidal soap or horticultural oil; these smother the insects.  Tree foliage insecticides will keep on killing for several years, but are more toxic.  Trees too large to spray can be treated with soil drenches or other chemicals that are absorbed and transported throughout the tree, but are not safe applied near bodies of water.  For whole forests, several insect species that feed exclusively on wooly adelgid were deployed beginning in 2002 in hopes of bringing the pest population down to manageable levels over the long term.  

A nice video pulls all this (and more) together here.

  

 

My own little darling at about ten years old is almost chest-high, and free of adelgid.

There are a dozen or so stands of eastern hemlock around my neighborhood, many consisting of several trees.  (Probably thirty or more trees of all sizes could be counted if including individuals in hedges.)  Of these, three stands have obvious signs of woolly adelgid.  There may well be more--I cannot closely examine trees in other people's yards.  My own was a tiny individual transplanted to the woods behind our house; ten or so years later it is only waist-high, but free of insects.  If landowners keep an eye on their own trees and treat them if needed, I have hopes that the spread of the insect can be slowed--at least locally. 

What can you do?  If you have any hemlocks, watch them.  If you find woolly adelgid, consult with state agencies on what treatment would be best.  If you see the insect on your neighbor's tree, let them know.  Don't move an infected tree to a new location.