SelecTree: Right Tree Right Place
Trees & shrubs are an important part of the environment and the communities that we live in. Use the health and safety links below to help avoid future conflicts with your valued plantings.
Planting or pruning trees near utility lines requires careful consideration. Look for the utility friendly icon in search results lists. See Utility Precautions for more information. Power line friendly tree species may grow taller than 25 feet due to local growing conditions and may require pruning or removal. Feel free to contact your local utility to request an arborist for a site consultation.
Tree species and location can influence the fire safety of your home. Although all vegetation can burn, research has shown that some resist fire better than others. Care should be taken to lessen factors that contribute to their flammability and hazard.
Live in a fire risk area? Please check with your local Fire Council or Fire Department before planting trees!
SelecTree provides Fire Resistance information as reported in The UC Forest Products Laboratory, Vegetation Guide for Landscaping in High Fire Risk Areas, 1997. Current information on this resource is available at UC Forest Products Laboratory - PreFire Engineering. Fire safety information within SelecTree is as follows for each associated listing*:
Favorable fire performance rating is based on the following characteristics:
- a low surface area to volume ratio, such as plants with thick, broad leaves as opposed to those with narrow, needle-like leaves.
- a high moisture content, as found in succulents and other plants with fleshy foliage.
- a low percentage of dead matter or debris.
Unfavorable fire performance rating is based on the following characteristics:
- a high surface area to volume ratio.
- a low moisture content.
- a high percentage of dead matter or debris.
Conflicting fire performance rating is based on being listed as fire resistant in some references and as fire prone in other references.
* (WARNING! Only 305 trees have this information in SelecTree. Using this category in a characteristic search will limit matching trees considerably.) Search Trees by Characteristics - see "Fire Resistance"
Root damage is usually caused when tree roots remain close to the surface of the soil. Tree roots can cause costly damage to paving, structures or even water and sewer lines. Because roots nearer the tree trunk will enlarge earlier and grow more rapidly, care should be taken to space trees appropriately from structures. Local environmental and tree care conditions, such as soil type or watering habits, can affect a tree's root development. Long, deep waterings can encourage downward root growth. Shallow soils will force roots to grow horizontally rather than vertically.
The SelecTree "Root Damage Potential" category attempts to qualify the tendency trees have of causing damage with their roots. The terms 'Low', 'Moderate' and 'High' are used in this category. Avoid planting trees with high root damage potential near structures.
Look for "Root Damage Potential" in the Search Trees by Characteristics.
Most plants sold at California nurseries are not in the category of invasive plants and will not invade or harm wildlands. Some plants however are vigorous and aggressive plants which can be invasive in the right environment. Invasive plants harm the environment by displacing native plants and wildlife, may increase fire danger, consume water, reduce recreational opportunities, reduce or destroy production from ranch and forest lands, and take funding from other programs to fight their establishment and spread. Please select non-invasive plants your area.
Natural areas are damaged by invasive plants. If you live in or near a natural area, invasive species should not be planted. SelecTree provides a California Native filter to aid in your search.
SelecTree's invasive plant information is reported from Cal-IPC California Invasive Plant Council and is displayed in the tree notes or memo section of the tree report.
Invasive plants are rated as High, Moderate and Limited.
- High - species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure.
- Moderate - species have substantial and apparent but generally not severe ecological impacts on physical processes, plant and animal communities, and vegetation structure.
- Limited - species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score.
Hazard tree information is an important component of the information required for successful tree ownership and care. Correct tree selection can help avoid future hazards and conflicts as the tree matures.
Trees with defects in trunks, roots or branches can fail creating the potential for property damage or even personal injury. Please use the links below for gathering information.
Appropriate tree selection for your planting location will lessen maintenance pruning and excessive green waste. Tree maintenance and greenwaste reduction begins with proper species selection and good landscape design. After selecting the right tree and the right location, proper planting, watering, feeding and pruning will lengthen a tree's life, maintain its safety and improve its aesthetics.
Proper planting involves establishing the appropriate depth, providing proper growing medium, and establishing a support system for the tree.
Follow up care should include watering, mulching and minor pruning as needed.
Pruning is a key component to successful plantings. Reasons for pruning include safety, health, and aesthetics. Poor or improper pruning can lead to weak, diseased and unsightly trees. Each cut should be carefully considered and appropriately made. Proper pruning techniques are described in the following online resources.
Allergy & Toxicity
Some plants produce substances or allergenic materials which can harm humans or animals who come in contact with them.
SelecTree provides toxicity information under the attribute "Health Hazard" and is defined as follows:
- Allergy = the tree may cause an allergic reaction due to its airborne pollen or a chemical it extrudes onto its bark or leaves.
- Irritant = some aspects of the tree such as plant hairs, oils or odor may cause irritation to the skin, eyes, nose or throat.
- Poisonous = a substance produced by the tree can cause injury, illness or death.
Search Trees by Characteristics - see "Health Hazard"
Poisonous Plant Information Database - Cornell University
Poisonous Plants - Univ. of Pennsylvania
Some Plants are Poisonous - Purdue Univ.
Allergy Free Gardening
Biogenic Emissions is an important consideration when large-scale tree plantings occur. This is especially important if air quality in the area is already poor. The information contained in SelecTree is taken directly (with permission) from the paper Low-Emitting Urban Forests: A Taxonomic Methodology for Assigning Isoprene and Monoterpene Emission Rates, by Michael T. Benjamin, Mark Sudol, Laura Bloch and Arthur M. Winer. Atmospheric Environment. Vol.30, No.9, pp.1437-1452, 1996.
Look for "Biogenic Emissions" in the Search Trees by Characteristics.
Trees are classified as 'Low', 'Moderate', or 'High', based on "the sum of the hourly emission rates of isoprene and monoterpenes, expressed as microgram emissions per gram dry leaf weight per hour", as follows:
- Low = less than 1 microgram total emissions
- Moderate = between 1-10 microgram total emissions
- High = greater than 10 microgram total emissions
(WARNING! Only 234 trees have this information in SelecTree. Using this category in a characteristic search will limit search results.)
Csiky, O., and G. Seufert. 1999. Terpenoid emissions of Mediterranean oaks and their relation to taxonomy. Ecol. Appl. 9: 1138-1146.
Geron et al., 2001, Isoprene emission capacity for US tree species, Atmos. Environ. 35: 3341-3352.
Harley et al., 1998, Emission of 2-methyl-3-buten-2-ol by pines: A potentially large natural source of reactive carbon to the atmosphere, J. Geophys. Res. 103: 25,479 - 25,486.
Karlik, et al., 2002, A survey of California plant species with a portable VOC analyzer for biogenic emission inventory development, Atmos. Environ. 36: 5221-5233.