Posts Tagged ‘larch sawfly’


The Eastern Larch, or Tamarack (Larix laricina) is an interesting tree, a conifer that is not evergreen. Rather, it is deciduous, shedding its leaves, or needles, every fall. Other conifers retain their needles for two to ten years, thus maintaining their green colour year round. The larch is quite attractive and distinctive in every season. In winter, it presents an interesting silouette, with its nubby, dense branches. In spring, the fresh new soft green needles lend the tree a feathery appearance. However, it is in the autumn that the larch really shines. As the year advances towards winter, the larch needles turn a vibrant gold. After the brightly coloured maples and oaks and other deciduous trees have lost their leaves, the larch trees stand out against a background of brown branches and dark evergreens, glowing brightly even on the drabbest day.


The Eastern Larch is wide-ranging. It can be found from Maryland north to the taiga, and across the continent from Newfoundland to Alaska. In spite of its wide range, it rarely forms pure stands and makes up only one percent of the softwood trees of Canada. It is quite adaptable, but is most commonly associated with wetlands and damp areas. It favors fens, which are less acidic than bogs, and have some minimal water flow bringing nutrients. Larch trees have shallow, wide-reaching roots that help to protect fragile soils and prevent erosion at the edges of wetlands. Trees grow to a height of 50 to 70 feet and live for 60 to 80 years, on average.


Small cones, less than an inch long, are produced and heavy seed crops occur every three to six years. Studies have found that up to half of the seed crop that drops to the ground is consumed or cached by small rodents and shrews. American Tree Sparrows and Red Crossbills are said to favor larch seeds and grouse feed on the needles and buds. Porcupines are fond of the inner bark and may damage the trees as they chew away large patches.

Many larch were destroyed in the early part of the twentieth century by a larch sawfly (Pristiphora erichsonii)epidemic. These needle defoliators virtually wiped out most old-growth stands of larch in eastern North America. The epidemic subsided after most of the larch population had died. Recurring infestations have varied in impact across regions. Fortunately, a few survivors carried on and in this area we are fortunate to be able to enjoy a good representation of the species.


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