WIND HAZARDS TO TREES
Well, Hurricane Isaac is barreling it’s way through the gulf coast, and there’s no better time to prepare homeowners and businesses for the onslaught of hurricane weather that always visits us in the fall. In order to protect trees from the harsh winds of a hurricane or tornado, pruning is necessary. People who have their trees properly pruned on a 3-to- 5-year cycle experience less tree damage than those who let nature do the pruning. Fall and winter are the best times to prune most trees. There are several reasons why the colder weather is preferred for pruning. First and foremost is the health of the tree:
• Deciduous trees are dormant dur- ing the colder months, therefore mak- ing them less susceptible then to insect and disease problems. After pruning a healing process occurs whereby cuts and wounds close natu- rally. This process is most active in the Spring when trees return from dor- mancy and begin their new growth. Late fall or winter pruning allows pathogens the least time to attack a wound in a tree.
• Tree pruning in late fall and win- ter, when the ground is frozen, also makes sense because it saves garden plants, understory trees and shrubs from damage by falling limbs.
• Tree pruning in late fall and win- ter, when the leaves are gone, enables the pruner to prune limbs more effi- ciently.
• Mature Sycamores, Maples, American Elms, and Oaks are all per- fect candidates for pruning this time of year.
• When pruning in all seasons, weight reduction at the ends of outer canopy branches is essential, in addi- tion to removing weak, diseased, and dead limbs.
We prune for aesthetics, we prune for tree health, and new research confirms the need to prune for safety. Recent research conducted at Kent State University examines the hazard posed by trees to human health and life during severe weather. Data main- tained by the National Climatic Data Center tracks information on storm fatalities in the United States. These data reveal that fallen trees accounted for 407 deaths between 1995 and 2007.
Tree species vary in their resistance to breakage, or being uprooted. For hardwood trees, such as Oak, Maple, Birch and Ash, a three-second gust of 74 mph will break large (greater than 1 inch) branches. Winds at 91 mph will uproot trees, and at 110 mph will snap tree trunks. For softwood trees, such as Pine, Spruce, Fir, and Hemlock, a three-sec- ond gust of 75 mph will break large branches, winds at 87 mph will uproot trees, and at 104 mph will snap tree trunks. These are not absolute num- bers but a value near the middle of the range of minimum wind speeds is expected to cause the damage.
People will always live and spend leisure time around trees, which pro- vide many benefits to our environ- ment. Meanwhile, the legal liability of tree owners for damages caused by fallen trees has been rising in the United States. The risks from fallen trees are strong reasons why regular pruning will help maintain your trees in struc- turally sound condition.
What a year! Ample rain started the growing season in a per- fect way. Then came a five- week drought that left us all begging for rain. August turned out to be one of the wettest months and it looks like more is on the way. So, what does this mean for our trees? Surely lots of water has to be great for them, right? The answer is not so simple. While the rainfall did provide a temporary solution to a lack of soil moisture, the extent of the rain caused some adverse effects.
Many trees have suffered from late- season foliar blights due to all the wet weather. Fungi thrive in damp, moist environments. Over-saturated soil has led to some adverse reactions of species that don’t particularly care for “wet feet,” where roots stand in water.
Fertilization of your trees will help reduce the effects of this year’s heavy rains. Pines, Arborvitae and Hemlock, to name a few, aren’t happy with the con- ditions we’ve had. You may have noticed that your trees experienced a late-season flush of growth, or that your Horse Chestnut tree actually re- foliated after contracting its annual leaf blight.
Tree fertilization to help your trees deal with this environmental stress is of utmost importance this year. Keeping trees fed will also help replace some the nutrients that may have been flushed out of the soil during flooding. Pruning your trees this fall or winter is something you should consider.