History of the Forest Resource

• 1832-1854 - 6.7 million acres (Surveyor’s Notes)

History of Iowa’s Forests

• 1954 - 2.6 million acres (USFS)

• 1974 - 1.6 million acres (USFS)

• 1990 - 2.1 million acres (USFS)

• 2003 – 2.7 million acres

Where do we find trees living in Iowa ?• In general - areas too wet or

too steep for agriculture.• So you find trees around

rivers and streams• steep slopes• urban areas as park and

yards• in protected areas, like State

and County Parks, Recreational Areas, and State Forests.

Taking InventoryJohn Burroughs, the nature writer, once said, “Be imaginative with

facts, but don’t imagine your facts.”

• Accurate information is the foundation for good decisions.

• In managing a forest for sustainable resources and benefits, the best way to obtain facts is by inventorying the woods and systematically compiling information.

Forest Measurements

• The two most important measurements that must be taken are tree diameter and height.

Diameter:

• A standing tree bole has a tapering form. • By general agreement, a tree’s diameter is measured

at “Breast Height” or 4 ½ feet above the ground (on the uphill side). This is expressed diameter at breast height or “DBH”. Exceptions are made when an irregularity or unusual swelling occurs at DBH, in most cases you go above the DBH.

• Diameter is sometimes measured with large calipers, but more commonly by a diameter tape or Biltmore stick.

Biltmore Stick• The Biltmore stick (named for the

cradle of US Forestry at Biltmore estate in North Carolina) is a straight wooden stick which is held against the tree.

• DBH is read directly from it.

• It works on the principle of similar triangles.

• Usually, the eye is held 25 inches from the stick and the stick is placed horizontally against the tree.

Tree DBH

• Because a tree does taper and even has different shapes, you should always take two measurements at right angles and average the results.

• When measuring trees, keep in mind the concept of DBH and the 4.5 foot measurements, and move your eyes and not your head

Height

• The Merritt Hypsometer works on the principle of similar triangles. First measure or pace out a 100 feet from the tree you wish to measure.

• Next hold the yard stick vertically 25 inches from your eye. Sight the zero inch mark at the base of the tree. Next sight along the stick to the top of the tree using your eyes only and read in inches the tree’s height. For every inch, the tree will have four feet of height.

Forest Stocking or Density:

• Measuring forest density involves determining the number of trees on a given area. You could measure every tree in the forest, but that would take lots of time or you could sample survey.

• One instrument to measure density or “Basal Area” (area occupied by wood) is to use a “prism”..

• The forester stands at a plot center, keeping the prism over the center and spin slowly around viewing each tree.

• The forester counts all trees that have trunk not visually separated by the prism and are considered in the plot.

Growth and Yield

• You can determine a tree’s age by cutting it down and counting the annual rings – but there is another tool that is less destructive that is used to determine age and growth is called the increment borer that produces a sample piece of wood, with the annual rings being visible.

• Counting the rings gives you age to the diameter of the tree, but also measuring the last inch can determine how many years it will take to growth another two inches in diameter..

Forestry Management Principles

• Stewardship

• Silvics

• Regeneration

• Improvement

• Protection

• Products/Utilization

Stewardship Planning for Management

• Deciding what you want - goals/objectives

• Find out what you have– trees, soils, slope, wildlife, understory, etc.

• Identify potential management options– Improvement– Regeneration

• Sustainability?

Silvics - Forest Ecology

• Site Characteristics– soils, amount of sun, drainage, slopes, etc.

• Climate– Rainfall and Sunlight

• Tree Characteristics– Growth– Shade Tolerance– Spacing

Regeneration

• Natural Regeneration• Artificial Regeneration

– Direct Seeding

– Seedlings

• Silvicultural Systems– Clear Cutting

– Seed Tree

– Shelterwood

– Selection System

Silvicultural Examples

• Clear Cutting

Silvicultural Systems

• Seed Tree

Silvicultural Systems

• Shelterwood

Silvicultural Systems

• Selection System

Woodland Improvement

• Timber or Forest Stand Improvement

• Pruning• Basically

concentrating the growth on the best trees or branches

Protection

• Insects• Diseases• Storms• Invasive Plants• Humans

Products/Utilization

• Wood Products• Fruits• Mushrooms• Wildlife (Deer and

Squirrels for Gabe to Shoot)

• Recreation• Carbon Storage• Watersheds• Fall Colors, etc

Why the Increase/Decrease?

• Land formerly classified as pasture was reclassified as timber due to the decline of the cattle industry in Iowa.

• Urban Development

Iowa’s Forest Ownership

Composition of Iowa’s Forests

• Iowa timber is primarily hardwood trees

Composition of Iowa Forests by Percentage of Total Acres

Cottonwood, 1%

Bur Oak, 4%

White Oak, 5%

Elm/Ash/Soft Maple, 24%

Maple/Basswood, 26%

White Oak/Red Oak/Hickory,

38%

Other Conifers, 0%

Red Cedar, 1%

White Oak

Red Oak

Bur Oak

Maple

Basswood

Ash

Eastern Cottonwood

Eastern Red Cedar

Bitternut Hickory

Shagbark Hickory

Hackberry

Black Cherry

American Elm

What Condition Are Iowa’s Trees And Forests In?

• What impacts the health of our forests?

• These Impact and Shape our Forests of Today and Tomorrow!!

Potential

• According to the US Forest Service Iowa’s forests are only growing 1/3 of their potential.

• What could we do to increase tree growth in our forests?