Steps to reforestation success after wildfire

How does vegetation recover after wildfires?

A forest can recover from fire slowly or in spurts, depending on several variables:

• The severity of the fire. After a low-severity fire, forests can rapidly regrow. Forests that suffer high-severity fires can take longer to recover.
• The type of vegetation. Grasses, forbs, shrubs and hardwood trees generally return on their own, even after a severe fire that kills most trees. These plants can resprout or regenerate from seed stored in the soil. Conifer regeneration depends on the proximity of seed trees. Most seed falls within one or two tree lengths of the seed tree. Conifer regeneration also depends on the timing of good seed crops, having a receptive seedbed (a postfire mineral soil seedbed is good for most conifers) and competition from other vegetation. All these factors must align for good natural regeneration. In practice, conifer regeneration can be spotty — from abundant to none.
• Whether you replant from seed or seedlings. It takes longer for conifers grown from seed to establish themselves than conifers planted as seedlings.

Encourage natural regeneration or interplanting

• Good for mixed or multiple objectives such as habitat and timber.
• Suitable for moderate severity, smaller high-severity patches.
• Not a “do nothing” option — must manage seedbed and competing vegetation.
• Longer timeframes for conifer establishment, less reliable.
• Interplant where regeneration is inadequate.
• Alternate reforestation plan required if salvaging.

Replant with or without salvage

• For moderate to high-severity burns.
• Can plant without salvage (may require site preparation) or after salvage.
• Suitable for mixed or multiple objectives, such as habitat and timber.
• Suitable for cases where reforestation is legally required after salvage.
• Compared to passive or natural regeneration, this option is more reliable and has shorter timeframes for conifer establishment. It offers more control over composition and genetics, but also higher costs.

Keys to reforestation success after fire

Plan ahead

In the unexpected event of wildfire, it is important to start as soon as possible. The first step is to assess the fire damage across your property, identify specific areas where you wish to plant trees and estimate the acreage of those areas. The basic steps are:

• Assess reforestation need in burned areas.
• Seek disaster-related assistance where needed.
• Match species and seedling type to site conditions.
• Order seedlings as soon as you know what you need. Anticipate delays due to availability.
• Prepare the site — anticipate delays when charting out the timing.
• Handle and plant seedlings properly.
• Control competing vegetation.
• Monitor animal damage.

Know your land

Getting to know your land is key to evaluating your planting environment and selecting suitable tree species and genetic types within species. This involves looking at:

• Soils and soil maps (available from the Natural Resources Conservation Service).
• Topographic features and microsites.
• Vegetation types and clues. An inventory of species can indicate soil and site conditions.
• Areas of full sun or shade.
• Known areas of disease and insect hazards.
• The potential for wildlife damage.

Use an appropriate seed source

Note that for a given tree species, it is essential to use an appropriate seed source to ensure that seedlings are from parent trees adapted to local conditions. For this, refer to geographic and elevational seed zones for Oregon. For more on matching species, seed zones and seedling types to your planting environment, see Selecting and buying quality tree seedlings.

A further consideration in selecting the seed source is the risk of climate change. Forest genetics researchers have concluded that current populations of trees are expected to be poorly adapted to future climates. Trees adapted to future climates may be found at lower elevations or farther south than current seed zones.

People may consider mixing seed sources to account for uncertainty and climate change over the life of a stand. However, there is no clear guidance for what is known as assisted migration. Look for “climate-based seed zones” to be developed over the next few years.

Avoid common problems

Proper attention to planning and implementing all key steps will help you avoid the most common causes of reforestation failure, including:

• Poor site preparation.
• Unsuitable or poor-quality planting stock.
• Improper storage, handling and planting.
• Competition for water and light from surrounding vegetation.
• Animal damage.

Be realistic

For many landowners, the timeframe for active reforestation is likely to be delayed beyond the normal one- to two-year period for planting after timber harvest. Due to the large areas burned in Oregon, we expect that the demand for tree seedlings and planting contractors will be much higher than the available supply.

Unless you already have contractors and seedlings secured, it could be two to five years before you can obtain seedlings and tree planters. You can use the extra time to seek assistance; assess your situation; observe natural recovery and regeneration; and plan your next steps.

Resources

Familiarize yourself with the basic steps of successful reforestation, covered in the following publications:

• Successful reforestation: An overview, EC 1498.
• Selecting and buying quality tree seedlings, EC 1196.
• Sources of Forest Tree Nursery Seedlings, Oregon Department of Forestry.