By CRAIG FREILICH
With all the warm weather earlier this spring, trees in the North Country might be a bit ahead of the average leaf “growth curve,” according to a Cooperative Extension forester.
But Paul Hetzler says the changeable weather – which also brought unseasonably cold temperatures and snow since temperatures rose to the 80s in March -- has caused some indisputable signs of damage.
Several days of record high temperatures followed by frosts and snow has happened more than once this year.
“If the leaves are out early and you get a hard frost, those young leaves in 28 degrees can be damaged,” Hetzler said. “You might see big holes in the leaves, as if insects have been chewing on them.”
This spring, Hetzler said, “I saw little maple leaves all over the snow. There have been some pretty substantial winds lately, and many leaves came off, and many more were damaged, looking tattered and bruised up. That makes them more prone to fungal disease. We saw that on some maple and ash last year.”
But Hetzler said that doesn’t mean the end of the tree, or even the end of leafing out this year.
“Substantial winds can rob a tree of strength, and if they lose enough leaves, they’ll put out a second flush.
“These trees have evolved over time. Their economics are pretty good,” Hetzler said. Trees “usually produce more sugar than they need and store it as starch,” and will use it if they need it.
“They can manufacture chemicals like a chemistry lab. They will convert sugars to complex hydrocarbons that act as a repellant to insects. Some insects are impervious, like caterpillars, but sometimes you’ll see “shot holes” in leaves, as if an insect had started munching, got put off, and left.
“But year after year conditions can chip away at their resistance and they become more prone to disease and insects.”
A late freeze can also damage flower buds, if they have emerged.
“They can sustain damage that’s not evident by observation. A freeze might not destroy the bud outright, but the flower can be damaged. You could get a sterile flower that will never produce fruit.”
But Hetzler believes the trees in the North Country, on balance, “are roughly even, and might still be a bit more advanced” for the time of year.
“They started out so fast in March. A lot of things advanced. Some might have lost some cold-hardiness,” to the point where they were ripe, so to speak, for damage in the cold.
So even with the warms spells followed by snows and cold, “they might still be more advanced than normal.
As for frost considerations for gardeners and farmers, Hetzler said the USDA recently revised its chart of safe planting dates in zones that, for instance, have traditionally put the North Country in an area where a killing frost might be expected up until June 1.
“The USDA maps are based on average temperatures. The average is warming but that doesn’t mean we can’t get temperature swings.
“Last year I took a gamble and planted early and got good corn. It was wonderful. Tomatoes, too.”
But he hedged a bit and held some plants out in case his gamble went bad.
“If you want to be on the safe side, you might still follow the June 1 date.”