Loss of Pine Limbs May Be Light or Water

Q. I have a large pine tree in a natural area losing limbs from the bottom up. It’s needles are browning and dropping. I don't water the tree much at all, but I have a water channel flowing 3 feet away on one side of the tree. The channel is mostly filled with moving water and is about 1 foot wide.

A. It's probably either water or light issue. Not enough light because trees are planted too close together will also cause lower limbs to die and drop. Sometimes light is not considered.  Pine trees planted four to six feet apart are too close together and lower limbs will die as they age.

An open canopy pine tree signaling that maybe the tree was either not receiving enough water OR it cannot get the applied water to the needles due to trunk damage.

            My guess is that it's water related; not enough. An easy way to find out is to put a sprinkler on the end of a hose and give the tree one to two hours of water once every three weeks to a month. I would use a non-oscillating sprinkler and adjust it to about 8 feet wide. Use a four foot long piece of rebar to adjust how many minutes to water.

Hose-end sprinkler.

            There are two ways that I use to tell if a pine tree isn’t getting enough water; 1) I look at the amount of new growth and 2) its canopy density. On well-watered, fertilized smaller pine trees to about 20 feet tall, I like to see about 18 inches of new growth and a solid canopy density. On older well-watered pine trees 40 to 60 feet tall the growth will be a lesser amount, perhaps 8 to 12 inches, but the trees still have a dense canopy.

If growth is 2 to 4 inches when the pine tree is older then growth is not enough. Measure growth at the end of May after spring growth is finished.

            Pine trees with drought problems usually grow 2 to 4 inches in length each year. This small amount of growth translates into a very open canopy. Because pine trees can have other problems as well such as borers and woodpeckers (sapsuckers), I inspect the trunk for this kind of damage as well. A tree trunk with extensive damage by borers or woodpeckers may also show signs of drought. Pine trees with only a few inches of new growth each year and an open canopy usually suggests drought.