I received a question from a reader in the Virginia City Highlands. Some of her trees are turning brown along with oozing lots of sap.
A small tree died and she has noticed some signs of beetle boring. She’s concerned that a larger nearby tree may have beetles and if she should treat it with something.
Singleleaf piñon pine, Pinus monophyla, is one of Nevada’s state trees. Piñon pine woodlands occur on many of the mountain ranges of Nevada. With development spreading into these woodlands, home landscapes often include piñon. Home-owners wishing to maintain these native landscapes need to know how to take care of the native pines.
Healthy trees have fewer insect and disease problems than trees that are stressed. It is important to keep trees vigorous by reducing human-caused stress factors such as improper irrigation, construction damage, soil compaction, and improper fertilizer or chemical use.
Piñon pines in home landscapes require minimal maintenance. They are growing in their native habitat, and therefore are adapted to the site. Piñons tolerate drier conditions better than other Nevada pines.
Irrigation and fertilization are typically unnecessary except when trees have been damaged by human activity or weather.
We often impact trees with our daily activities. Trees that have been injured, above- or below-ground, are prime candidates for attack by insects, such as borers, and diseases. Root damage is a common source of tree stress caused by humans. Root systems of piñon are often damaged by overwatering. Because their native habitats are drier than those of other pines, too much water can cause root problems and death.
Homeowners used to watering landscape trees such as Austrian (Pinus nigra) or Scotch (Pinus sylvestris) pines regularly through the summer, often mistakenly irrigate their piñons similarly. Piñon trees should never have irrigated landscapes planted around them. They need well-drained soils.
The piñon’s growth, starting in April and ending in September or October, is supported by stored soil moisture rather than spring or summer rains. Watering a piñon pine should mimic natural rain or snow, and should be done primarily from December to April, if a winter is unusually dry.
During periods of drought in winter and early spring, trees should be given a deep watering monthly. Keep water away from the root crown.
For information on keeping piñon pines healthy, identifying specific pests and managing those pests, please read “Piñon Pine – Management Guidelines for Common Pests” at http://forestry.nv.gov/wp-content/uploads/2018/10/Piñon-Pine-Management-Guidelines-for-Common-Pests-eb0302.pdf.
JoAnne Skelly is associate professor & extension educator emerita of the University of Nevada Cooperative Extension.