By: Anthony C. Arnoldi, Certified Arborist
In last spring’s issue of the Seasonal Report newsletter it was described how the effects of prolonged drought were manifesting on many spruce trees.
These effects were observed to be:
- needles drying
- needles falling off or becoming easily dislodged
- bare branch tips forming and becoming more numerous
- shedding of entire tips of the previous season’s growth
Precipitation records for southeast Wisconsin show that in the last several years we have received below normal amounts, with 2002 and 2003 being particularly dry. In fact, while it was hoped that 2003 would bring some relief, rainfall totals show that we were 12.5 inches short instead.
As a result, symptoms have been intensifying and showing up on even more spruce. Needle drop has continued throughout the winter—often being visible against the snow. More spruces are becoming offcolor as a result of continued drying. More calls are coming in for dead spruce, and most of these lost all of their needles in just a few months.
Getting supplemental water to these spruces has not always been easy. For one thing, many people are unaware of the need for it. The rains we have received have been remarkably timely so as to keep lawns from browning out significantly—the major barometer people tend to use to determine watering need. Therefore, watering has been sporadic, if given at all. Also, many people in suburban areas rely on their wells to supply this water. The concern is constantly voiced that watering their trees will burn out their well or make it go dry, or that repeatedly dragging hoses and sprinklers is especially difficult for them. All of these are valid concerns.
Conserving the moisture that does fall or that can be given must be a top priority. Mulching spruce or even increasing the size of the root area mulched will help. Increasing mulch depth to the full 4 inches allowable will conserve more moisture and better insulate roots from the hot, drying temperatures of summer. Watering in the early morning or in the evening will reduce losses to evaporation (but be sure to avoid wetting the foliage, especially if watering in the evening, to avoid promoting fungal infection of the needles). Wachtel will continue to offer watering as a service option for you as well.
However, if more moisture is not forthcoming, increased spruce mortality will surely be the result. For those spruce already damaged by the effects of drought, treatment to encourage the replacement of fine feeder roots will be necessary. This is because spruces with reduced feeder roots (lost from the dehydrating effects of dry soil) will struggle to pull in water even if rains return! Root zone injectionsof nutrients, root biostimulants or mycorrhizae may be prescribed. Call your professional Wachtel Certified Arborist for help in assessing your spruce’s situation.
© Copyright 2004 – Wachtel Tree Science & Service, Inc.