Weather deals tough, but not fatal, blows to wild Missouri - by: Jim Low

Story by: Guest Contributor

First posted on 04-30-2007

Record high and low temperatures created hardships for individual plants and animals, but natural resiliency will enable their species to persist.

The last week in March was the warmest in Missouri since record-keeping began 118 years ago. The first week in April was the coldest on record. Caught off guard by the yo-yo weather, some wild plants and animals suffered serious setbacks, but nature experts say the effects will be small and temporary.

Pat Guinan, a climatologist with the University of Missouri, said temperatures across Missouri were 14 to 16 degrees above average from March 21 through April 3. The following six days were 16 to 18 degrees below normal across the state. Missourians will see the effects of those back-to-back extremes in the coming months.

Forest health specialists with the Missouri Department of Conservation say the severity of frost damage to trees depends largely on how advanced leaf-out was. Trees in many parts of southern Missouri were as much as four weeks ahead of average when the cold weather hit, making damage there the most serious. In central Missouri, trees were two weeks ahead of normal leaf-out. Those in the northern part of the state were at a more or less normal level of budding and will be least affected.

Resource Scientist Bruce Moltzan said he has received a number of calls from people expressing concern about how morel mushrooms might be affected by the freeze. He said “morels are up and the frost has not impacted their arrival.”

The most serious impact from the freeze on wildlife likely will be reduced production of acorns and other “mast,” fruits that provide food for everything from deer and turkeys to rodents and insects.

Acorns are the primary type of “hard mast” - durable fruits from trees and shrubs. In any given year, there is a certain amount of natural crop insurance built into Missouri’s oak-dominated forests. White oaks produce fruit from flower buds that grow and mature in the same year. Red oak acorns come from flowers that formed the previous spring. So, while this year’s white oak acorn crop could be dramatically reduced in some parts of southern Missouri, acorns from red oaks likely will help buffer the loss.

Conservation Department Resource Scientist David Gwaze noted that acorn production is influenced by many factors, including weather, nutrition, overall tree health and previous year’s production.

“Mother nature works in mysterious ways,” said Gwaze. “There is a lot we do not know about the effects of frost damage on trees. The issue is made more complex by the fact that resistance to frost damage varies between trees, species, stage of growth and sites. We will not know for sure what the effects of this spring’s strange weather are until autumn.”

One effect Gwaze was willing to predict was that the George O. White State Forest Nursery at Licking will have fewer seedlings of some tree species in 2008 due to frost damage to developing seedlings.

The Conservation Department’s April 11 update on state forest health said the state forest nursery also may have difficulty finding white oak acorns to plant for next year’s seedling crop. It said trees that lost leaves to record cold will replace the foliage and be back on schedule by the end of May. The long-term effects will vary, however, depending on the freeze’s effects on insect pests.

Insects that followed trees out of dormancy could have suffered as much as their hosts. In those cases, trees will have a little advantage in replacing damaged foliage. However, other insects, which emerge later, could deliver a serious second blow to trees already low on reserves due to lost leaves. Tent caterpillars are cold-resistant and could cause particularly serious problems for trees this year. Being defoliated twice - once by cold and once by insects - could leave some trees seriously weakened. On the other hand, caterpillars could be in trouble if they emerge only to find their host trees without leaves to feed them.

To help landscape trees, the Forest Health Update recommends watering, mulching and fertilizing damaged trees. For more information, visit: intranet/features/20070410freeze.asp.

Small plants and animals suffered most. For example, some tree and shrub seedlings planted just before the surge of arctic air dropped temperatures into the teens were seriously hurt. With leaf and flower buds already opening, and their root systems not yet well established, they might struggle to replace frost damage. In some cases, frost damage could be so extensive the plants die.

Established trees and shrubs that were in good health before the several-day freeze will shrug off the damage. Those that were stressed by disease, parasites or declining vigor due to age could go into decline, though many will recover, given favorable conditions.

Small animals, such as rodents, lizards and salamanders, that can take cover are likely to fare well in spite of the cold. More vulnerable are birds, whose normal migration timing landed them in a deep freeze.

Among animals most visibly hit by the cold were purple martins. Male martin “scouts” begin arriving in Missouri as early as February. This year’s unprecedented warmth encouraged early arrivals. Conservation Department Ornithologist Andy Forbes said he has received numerous reports of martins that died, either from cold or from starvation when the untimely freeze killed all their insect prey.

“Cold, rainy weather is a killer for purple martins if it lasts more than a few days,” said Forbes. “Massive mortality can occur as a result. While this is unpleasant, it is common when these types of weather conditions occur, and normal. The martin population will rebound over the next few years.”

The Forest Health Report echoed this perspective.

“Trees are amazingly resilient and should come through with a new crop of leaves. Damage is going to be more severe in low-lying areas and in places that had the most consecutive days of freezing temperatures. *In the urban landscapes, proper tree-tending measures such as mulching, fertilizing and watering will go a long way in assisting your tree’s recovery.”

Fish are unlikely to suffer serious stress, thanks to the insulating properties of water. However, cold air, rain and snow could set back their spawning activity by weeks. That has been bad news for paddlefish anglers, whose sport is especially dependent on upstream spawning runs to locate fish.

Fisheries Management Biologist and paddlefish specialist Trish Yasger said this year’s paddlefish snagging season has been disappointing.

“So far, the weather is not cooperating,” she said. “With the decrease in water temperature and a very small increase in flow, snagging hasn’t been as good as it has been the last couple of years. Snagging has been very spotty to say the least. Cold rains and snow the first week in April kept water temperatures below where they needed to be to trigger a good spawning run. There is still a chance that warm weather and increased rainfall could give us some good fishing before the season ends April 30, though.”

-Jim Low-

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