Microsite Selection and the Informed Planter
A CRITICAL STEP
A Planter's Guide to Recognizing Optimum Microsites
Microsite Planting
What is it?
Microsite
planting is choosing the best location to plant a seedling to ensure its
optimum health and growth. This spot must have most of the good things a
seedling needs.
Why do it?
Planters
are the last critical link in the long chain of events that strives to grow
high quality trees. Being able to quickly select the best microsite will
increase seedling survival and growth and will greatly benefit the forest
that will follow.
What's in it for
the planter?
Planting
the best microsite does not have to slow you down! Generally, the best
microsite is the easiest to plant. You will learn that a good spot, such as a
natural raised mound, can have less rock or other impediments to planting.
Easier Planting = Faster Planting
Growth Limiting
Factors
Few
sites have all the right growing conditions in the ideal amounts. Usually a
site is lacking one or more necessary elements to the point that seedling
survival and growth is affected. This is a growth limiting factor.
Some of the most important ones are explained below.
Seedling
Requirements and Growth Limiting Factors
The
following conditions are necessary for seedlings to survive and grow.
- Air - required by seedling top and roots to grow;
- Light- needed to produce food and foliage;
- Soil - provides structure to support tree and to
distribute moisture, nutrients and air;
- Humus - important source of nutrients for tree growth.
Well decomposed humus should be maintained when planting a tree.
Soil - The Growing
Medium
Soil
is critical to the survival and growth of all plants including seedlings. Poor
soil structure can limit survival and growth. Pore space in soil is necessary
for air, water movement, and for roots to grow. Good soil includes
approximately 50% pore space.
Disturbed Soil
When
soil is compacted the pore space available for air, water and roots is
drastically reduced. When pore space is not available or is flooded, roots will
die back.
Avoid planting on skid roads and trails unless instructed to do 50 by your supervisor. The soil here is usually too compacted to support healthy growth of seedlings.
Soil Temperature
Soil
temperature significantly affects seedling growth. For example, where the
climate is cold and moist, a raised site provides better aeration/drainage than
wet, saturated soils and this results in warmer soil temperatures and better
root growth.
Soil Water
Soil
water is often a critical growth limiting factor. Raised microsites are
generally well drained while low microsites are usually moist. Roots need both air
and water to grow. Maintaining the proper balance is critical to good root
growth.
Moisture conditions vary from site to site and change during the year. If uncertain, ask if the site you are planting has a soil moisture concern and what is the best microsite to select.
Competing
Vegetation
Sometimes
seedlings must compete with the surrounding vegetation. On sites with
aggressive vegetation like salmonberry, thimbleberry and black twinberry, use
your spacing tolerance - plant away from the brush
Mechanical Site
Preparation
After logging, it is sometimes necessary to improve the natural microsites to ensure reforestation success. Treatments may include prescribed burning, herbicides, or more commonly, mechanical site preparation (MSP). MSP is site preparation carried out by machines. Different machines (e.g., disc trencher, mounder, drag scarifier) alter the site in different ways.
What Does MSP do?
- MSP creates well-drained microsites when the soil is
too wet.
- MSP creates sites that retain moisture when the soil is
too dry.
- MSP creates porous microsites when the soil is too
compacted.
- MSP creates raised planting spots that dry out and warm
up faster than the surrounding ground on cold sites.
- MSP clears competing vegetation out of the way to give
seedlings a head start.
Where
an area has had MSP, it is important for you to recognize the best microsites
and to know how to plant them. On MSP sites you should be told where to plant.
If in doubt - ask your supervisor!
MSP is expensive! It is
important to take advantage of MSP treated sites and plant correctly.
What Can a Planter
Do?
By learning
to better recognize and choose a microsite, a limiting factor or site condition
may be avoided and the seedlings will have a better chance of surviving and
growing.
The current survival rate averaged for the province, measured two years after planting, is an excellent 87 per cent. You as a planter have contributed to this success.
The Bottom Line
- Microsite planting is very important.
- If you are not sure where to plant...ask your
supervisor.
- The results of planting correctly will provide benefits
for a long time.
For
more information on microsite planting, contact:
Regeneration Specialist
Resource Practices Branch
B.C. Ministry of Forests, Lands, and Natural Resource
Operations
Victoria, B.C.
(250) 356-6932
En
Français | Ministry of Forests
| Forest Practices Branch