Forest Landscape Baseline No. 11 Brief Progress and Summary Reports 1995

AN OVERVIEW OF ANCIENT FOREST ECOLOGY IN THE
LAKE TEMAGAMI SITE REGION

P. A. Quinby

Introduction

Old-growth forests are valuable for many reasons. They keep soil from eroding away; help to keep water clean; hold on to nutrients which are very important for plant growth; provide large, natural areas which are required to maintain healthy animal populations; and by building up dead wood (snags and logs) instead of converting wood to carbon dioxide gas, they help to mitigate the problem of global warming (increased carbon dioxide leading to increased temperature at the earth's surface). The study of old-growth forests has also helped us to better understand the field of ecology.

The best known old-growth forests in central Ontario are the old-growth white and red pine forests. Sadly, however, less than one percent of the world's original old-growth white and red pine forests remain, which makes them "endangered ecosystems". If the few remaining old-growth forests are to be saved we must develop a better understanding of what they are and what makes them work. Water, light and fire are three of the most important factors determining the nature of ancient forested landscapes in the Lake Temagami Site Region.

Water is one of the most important resources that plants (including forest trees) need to grow and reproduce. It is used by the plant to make food, it brings nutrients into the plant mainly through the roots, and it transports materials within the plant to various parts. In the central Ontario forested landscape, the amount of water in the soil which comes from precipitation has a major influence on the kinds of plants which are able to grow, the size that the plant can attain, and how fast the plant can grow. The soils are driest on the hilltops where there is very little water buildup from rainfall. They are wettest in the valleys which receive water draining down through the soil from all the uphill areas next to each valley. Due to their particular abilities, white and red pine are generally common on the drier hilltops and less so in the wetter valleys where species such as white cedar, black spruce and yellow birch tend to do well. In addition, the amount (or volume) of plant growth in valleys and on lower slopes, where water is more plentiful, generally tends to be greater than on hilltops.

Light

Because of geater plant volume including a thicker forest canopy in valleys compared to hilltops, the amount of light that reaches the forest floor in the valleys is generally lower than on the hilltops. This has important effects on the kinds of trees that can reproduce and grow well in valleys compared to hilltops. Some species such as black spruce and yellow birch are better suited to germinate and grow in the shaded conditions of the valleys compared to species such as red pine and jack pine that require the more open, lighted conditions of the hilltops for germination and growth. In addition, the amount of light reaching the forest floor determines the kinds of understory herbaceous plants that can grow. For example, bracken fern is more typically found in the drier, more open environments of hilltops and spinulose wood fern is more typical of the wetter, darker valley floors. The more open conditions of hilltops and the resulting greater amounts of sunlight at the forest floor also contribute to drier soil conditions through increased evaporation.

Fire

Until only recently, fire has played an important role in the ecology of central Ontario's ancient forests. In these forests, fire tends to burn uphill due to winds that generally get stronger towards the hilltops. These strong winds on the upper slopes provide lots of oxygen to the fire which makes the fire burn larger and hotter. Thus, there are fewer fires in valleys than on hilltops. In addition, the wetter soil conditions in valleys helps to prevent fire and the drier soil conditions on hilltops tends to promote fire. Most forest fires do not destroy the entire forest. In central Ontario, fires most commonly burn along the forest floor killing a few large trees and many small plants, and reducing the thickness of the dead leaves and needles (litter) on the forest floor. When the litter is burned, the mineral soil below is exposed. This exposed mineral soil plays an important role in the germination and early growth of some tree species such as red and white pine. Red pine is particularly dependent on these wildfires for regeneration. Since wildfires have been suppressed in central Ontario, starting around the early 1920's, very little red pine forest has been regenerating naturally.

White and red pine trees in central Ontario are commonly found growing with at least 15 other tree species. The pines (including jack pine) often out-compete other trees on dry coarse-textured soils. Relative to red pine, white pine grows on a wider range of soil moisture conditions, however, red pine is usually more abundant on the coarser sandy soils, and white pine on the soils with finer sands and silt. With its limited extent due in large part to logging, the rarest of the old-growth white and red pine forest communities is characterized by tolerant (to shade) hardwood species such as sugar maple, yellow birch and American beech growing in association with large old white pine. It is often called the "white pine-tolerant hardwood" forest type. The density of white pine in this old-growth forest type is normally lower than when it grows in association with other conifers or early successional hardwoods such as white birch and poplar. However, the individual white pine themselves are often much larger and taller than those found in the other forest types. This is due mainly to the better growing conditions in areas where tolerant hardwoods are common.

Old-growth forests dominated by red pine are much less common in Ontario than those dominated by white pine. For example, in Algonquin Park, there is six times more white pine dominated forest than red pine dominated forest (most is intermediate to mature in age). In the Temagami Region, there is three times more white pine forest than red pine forest. In the Lower Spanish Forest near Espanola, however, initial studies indicate that there is as much red pine as white pine meaning that this area may have one of the highest concentrations of red pine forest in Ontario.

Ecological studies of old-growth white and red pine forests in the Temagami Region of Ontario (Quinby 1993) have produced minimum standards for these unique forest types (Table 1). These minimum standards for old trees, snags (dead standing trees) and logs can be used for field identification of old-growth pine stands or pine stands with one or two old-growth characteristics.

Table 1. Minimum standards for old-growth white and red pine forests in Temagami, Ontario

One of the most valuable features of old-growth white pine forests is their frequent ability to replace themselves whenever they are not significantly affected by human activity (Quinby 1991). By studying the processes of natural white pine regeneration in ancient forested landscapes, we may learn enough to successfully restore and regenerate previously logged white pine areas that are now dominated by other plant communities. Old-growth white pine stands in the Temagami Region that have not been fragmented by logging are almost three times healthier in terms of white pine regeneration (Fig. 1).

Figure 1. White pine regeneration in natural (unfragmented) and fragmented old-growth white pine forests in Temagami, Ontario Only one study has evaluated the later stages of white and red pine forest succession as animal habitat. This study identified animals that need or prefer older white and red pine forests to complete some or all stages of their life cycle including species of amphibians, birds and mammals (Table 2).

Table 2. Animal species with preference for at least one mature/old-growth white and/or red pine forest community type in Ontario (adapted from Bellhouse and Naylor undated)

References

Bellhouse, T. and B. Naylor. undated. personal communication. Ontario Ministry of Natural Resources, Central Region Science and Technology, North Bay, Ont. (from Clark and Perera 1995).

Clark, T.P. and A.H. Perera. 1995. An Overview of Ecology of Red and White Pine Old-Growth Forests in Ontario. Ontario Forest Research Institute, Ministry of Natural Resources, Sault Ste. Marie, Ontario. 29 pp.

Quinby, P.A. 1991. Self-replacement in old-growth white pine forests of Temagami, Ontario. Forest Ecology and Management 41:95-109.

Quinby, P.A. 1993. Definitions of Old-Growth Eastern White Pine and Red Pine Forests for the Temagami Region of Ontario. Forest Landscape Baselines No. 3, Ancient Forest Exploration & Research, Toronto, Ont. 4 pp.

Quinby, P.A. 1994. Influence of Logging, Stand Size and Stand Shape on the Regeneration of White Pine in Old-Growth Forests. Forest Landscape Baselines No. 5, Ancient Forest Exploration & Research, Toronto, Ontario. 4 pp.

Produced by Ancient Forest Exploration & Research, 93 Westmoreland Ave., Toronto, Ontario M6H 2Z8; phone (416) 535-0205; A summary report of the "Conservation Strategy for the Lake Temagami Site Region Project"; funding provided by The Richard Ivey Foundation, The Ontario Heritage Foundation, Earthwatch, The Helen McCrea Peacock Foundation, The George Cedric Metcalf Charitable Foundation, and the Ontario Ministry of Natural Resources

Forest Landscape Baselines are a periodic publication of Ancient Forest Exploration & Research, a non-profit charitable organization dedicated to the study, protection and scientific application of ancient forested landscapes. Our publications are available online at www.ancientforest.org/publications.html Back to top of page Back to Publications