Ask the Steward
By Dan Ernst
I heard black locust was once used to make nails for ship building. Is that true?
Black locust is one of the hardest and densest woods grown in North America. It is tougher than nearly all Indiana woods- only osage orange is tougher. Because of its unique qualities black locust wood has been used to satisfy many special applications. Ship building is just one of those uses and is still a species of choice for many wood ship building applications. As for wooden nails: black locust is a favorite for wood pegs in post and beam barn building and restoration projects due to its toughness and low shrinkage. Locust tree nails for ship building are sometimes called ‘trunnels’ and have certain advantages over steel nails. For one, they do not corrode like steel nails exposed to salt water. Also, as water seeps into the end grain the trunnel expands forming an even tighter seal.
Additionally black locust is a favorite for fence posts due to its high resistance to decay. Fence posts of black locust may last 20, 30, 40 years or more. Locust is also a favorite for xylophone keys. It was used as mine props due to its great structural strength- some were even hauled to California during the gold rush.
Don’t rush out to plant this species, however. In Indiana it is considered somewhat invasive as it spreads by suckers and can form dense groves. It also has insect problems – most notably locust borer and the locust leaf miner, which sooner or later affects most all black locusts.
After the drought and heat wave of 2012 my woods has several trees that look sickly. Will they die?
Last year was indeed a record year for heat and drought covering much of Indiana and the Midwest. Additionally, the outbreak of tulip tree scale made for a perfect storm of tree stress in south central Indiana. Among the most affected areas are Owen, Monroe, Putnam, Jackson, Bartholomew and Brown counties. It indeed was the harshest summer conditions in my career.
The result will be many thousand dead trees across Indiana. This includes yard and urban trees that were planted in tough conditions outside their normal environment and quickly succumbed to the bone dry conditions. Hemlock and Northern White Cedar were common early casualties due to their need and preference of moister soil conditions.
In the forest, tulip tree, dogwood and understory sugar maples were notably hard hit, but this is part of the natural selection process. The impacts of the drought on trees will be felt for 2-5 years. Many of the severely and visibly affected trees will die within the first year - but certainly not all. I have seen tulip trees with 50% leaf drop survive just fine after subsequent years of normal precipitation.
Surviving year one is a good sign, but does not guarantee survival. Stressed trees can also be affected by secondary pests, such as two lined chestnut borer and Armilliria (shoestring) root rot. Trees can usually fight of one of these pests just fine, but in a weakened state secondary attacks can take their toll. In some case affected trees will appear healthy and recovering, only to die in year 2, 3 or 4, but with each passing year the chance of survival climbs significantly.
What can you do? As a forest owner walk your woods now while in full leaf out and monitor tree crown conditions. Watch for trees with greater than 50% unhealthy crown and epicormic sprouting. If only a few trees are affected, there is little for you to do. If large numbers of trees are looking bad, contact a forester for woods inspection as discuss the advisability of a selective harvest.
Dan Ernst is an Assistant State Forester with the Indiana Division of Forestry. He oversees the state forests in Indiana and has authored the “Ask the Steward” column for years. Have a question for the column? Email Dan at email@example.com.