Masters Theses

Date of Award

5-1999

Degree Type

Thesis

Degree Name

Master of Science

Major

Landscape Architecture

Major Professor

John W. Day

Committee Members

Donna Fare, Willard Witte

Abstract

Recently there has been a growing Interest and demand for alternative species. Native species are receiving much interest not only as alternative species but for their environmental value. Native species are usually better adapted to the soils, climate, rainfall, pests and soil microorganisms in their geographical range. They help in the retention of regional character, maintenance of biodiversity, prevention of exotic invasions and creation of more suitable habitat for native wildlife.

The purpose of this project was to determine optimum cultural practices for three native species thought to have considerable landscape merit - Carpinus caroliniana Walter (American hornbeam), Fagus grandifolia Ehrhart (American beech) and Gymnocladus dioicus (L.) K. Koch (Kentucky coffeetree). Research was conducted to determine the effects of: (1) seed stratification and scarification regimes, (2) light quality and photoperiod, (3) shade level, (4) fertilizer rate, (5) container size and (6) ectomycorrhizae on germination rate, stem height, stem caliper, dry weight of roots and shoots and quality of seedlings after one or two growing seasons.

Germination of C. caroliniana seeds was greater after 20 or 24 weeks of cold stratification compared to 4, 8, 12 or 16 weeks. Germination was further increased after 4 or 8 weeks of warm stratification compared to 0 or 2 weeks. Germination of F. grandifolia seeds was greater after 14 or 16 weeks of cold stratification compared to 12 weeks. No difference in germination of G. dioicus seeds was found between 2, 4 or 6 hours of scarification with concentrated sulfuric acid (86.5, 95 and 86.5% respectively).

After 12 weeks, C. caroliniana seedlings grown under 18 hour photoperiod and high pressure sodium lights (HPS) were taller than plants grown under 18 hour photoperiod and incandescent lights (INC) or natural light and daylength (NAT). F. grandifolia seedlings grown under the HPS and INC treatments were taller than plants In the NAT treatment after 14 weeks. No ill growth differences of F. grandifolia were found between the HPS or INC treatments. After 12 weeks, G. dioicus seedlings grown under the HPS and INC treatments had greater growth in height and caliper and root and shoot dry weight than those under the NAT treatment. The HPS and INC treatments also caused a higher percent of G. dioicus seedlings to produce a second flush of growth.

There were no growth differences between C. caroliniana seedlings grown under different light intensities (full sun, 30% shade and 60% shade) after 21 weeks. F. grandifolia seedlings showed no growth response to light intensity after 22 weeks.

After 22 weeks, shoot dry weight of C. caroliniana seedlings grown in 3.8 L containers was greater than those grown in 5.7 L or 7.6 L containers. No differences were found in growth of height or caliper or root dry weight. Container size did not affect growth of F. grandifolia seedlings.

Increased rates of 18N-2.6P-10K fertilizer resulted in decreased height growth of C. caroliniana seedlings. Plants grew taller under the lowest fertilizer rate compared to the medium and high rates. Increased fertilizer rates (18N- 2.6P-10K and 14N-6.1 P-11.6K, respectively) did not affect growth of F. grandifolia or G. dioicus seedlings.

Ectomycorrhizae (Pisolithus tinctorius) did not increase growth of C. caroliniana or F. grandifolia.

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