The need for long-term forest inventory and
monitoring results continues to dominate forest health issues
in Maine. Annual collection of Forest Inventory and Analysis data using
a standard national plot design and core measurements is underway. The
survey integrates the traditional forest inventory with the Forest Health
Monitoring Program to assess forest condition, including trees, soils,
lichens, and ozone bioindicator plants.
Most trees damaged by the ice storm of 1998
now show significant recovery of affected crowns. Tree species that
possess the ability to produce sprouts in damaged portions of their
crowns displayed lush foliage in 2000 and were aided substantially by
a moist spring and early summer. Species that have recovered best from
significant crown loss in 1998 include white ash, red oak, and sugar
maple. Trees that lost more than 75 percent of their total crown now
have smaller, but apparently normal, crowns. Several other species,
such as red maple and aspen species, show improved crowns but to a lesser
degree. Softwood species that lost significant portions of their crown
show little or no crown recovery. Also, several hardwood species such
as birch and American beech apparently lack the ability to rebuild their
crowns significantly through sprouts and show little recovery.
There are currently concerns over threats to the forests from recently
introduced pests. The hemlock woolly adelgid,
which is causing mortality of eastern hemlocks in the eastern United
States, was inadvertently imported into Maine on a shipment of infested
nursery stock in April 1999. Ninety percent of the trees have been removed,
although most appeared to be uninfested. A statewide detection effort
was launched and the adelgid was identified at 10 ornamental outplanting
sites in central, coastal, and southern Maine in Penobscot, Hancock,
Knox, Lincoln, Sagadahoc, and York Counties in 2000. In 2001, this pest
was detected and eradication efforts were implemented at 15 sites in
York, Penobscot, and Waldo Counties. Treated sites will be monitored
for a period of 5 years. At this time the adelgid is not established
on native hemlocks in Maine.
The European pine shoot beetle, a
pest of pine, was recently discovered in northern New Hampshire, Vermont,
and Quebec. One specimen of this beetle was collected for the first
time in Maine in Oxford County during the spring 2000 trapping survey
conducted in central and southern counties. Two beetles were trapped
during the 2001 survey. No infested trees or damage were found during
ground surveys. Oxford County was placed under an interim quarantine
rule in July 2001 by the USDA Animal and Plant Health Inspection Service.
Another exotic pest, the browntail moth,
continues to infest islands in Casco Bay and on the nearby mainland.
The generally infested area extends from York to Hancock Counties; however,
there has been a reduction in the total area affected. Spray projects
were carried out in Brunswick and Portland to reduce populations of
the caterpillar, which has hairs that cause serious skin rashes.
This is the second year that European gypsy
moth populations increased in southern and central Maine, resulting
in widespread defoliation of 29,365 acres of hardwood lands in 2001.
Feeding was very intense in portions of York and Cumberland Counties,
with heavy defoliation of sapling and pole-size white pine in many locations.
Other conifers with forest health problems in Maine include spruce,
larch, and white pine. Spruce trees
along the coast and offshore islands around Penobscot Bay continue to
be impacted by spruce beetle and dwarf mistletoe. There are increased
areas of larch decline and mortality,
a result of larch beetle and defoliators attacking drought stressed
trees. Eastern white pine stands in
southwestern Maine have been exhibiting decline symptoms associated
with previous drought stress.
The quarantine for larch canker is
still in effect along coastal areas. Butternut
canker, first reported in Maine in 1993, has now been located
throughout the State, except Washington County.
In addition to annual pest surveys, ongoing
monitoring efforts include evaluation of insect populations associated
with various current forest management regimes. Cooperative forest health
projects underway include reevaluation of forest regeneration in spruce
budworm damaged stands within Baxter State Park and studies on
the yellowheaded spruce sawfly in black
and white spruce plantations in central Maine.