What Is a Healthy Forest? A Supplement to Florida Project Learning Tree1

Sarah L. Hicks, Martha C. Monroe, Geetha S. Iyer, and Jason A. Smith 2

This supplement is available in pdf form here: https://edis.ifas.ufl.edu/pdffiles/FR/fr35400.pdf

The forests of the Florida are indispensable. From the cypress swamps and longleaf sandhills along the Blackwater River to the mangroves that hug the Florida Bay, this state supports a diversity of forests. These forests form a network of temperate to subtropical ecosystems that shelter animals as small as bark beetles and as large as black bears.

They support humans as well, in both tangible and intangible ways. They are a source of aesthetic beauty and regional pride. They are an economic resource in sectors ranging from timber and fiber production to recreation and tourism—timber alone is a multi-billion dollar industry in the South. In addition to the monetary value of forest products is the value of the ecosystem services that forests provide. They hold together soil and filter water, photosynthesize and produce oxygen, recycle nutrients and store carbon, and serve as a gene bank for countless organisms. It is essential that these forests remain healthy and productive to benefit all the life forms that rely upon them.

A healthy forest is an intricately balanced system of interacting parts. Climate influences environment, environment shapes plant growth, plants provide food for numerous other organisms, and humans intersect with this system by harvesting and planting, fragmenting and reshaping, analyzing and appreciating forests for a variety of purposes.

Historically, concerns about forest health overwhelmingly focused on the eradication of undesirable pests and disease-causing pathogens, such as insects and fungi, or environmental disruptions like fire, which could weaken or kill trees. However, damage, decay, and destruction are an essential component of healthy forests. Insects that feed upon trees are fed upon in turn by other animals. Fungi that rot away trees replenish the soil with nutrients that would otherwise be locked away in wood. In fire-dependent ecosystems, fires clear the undergrowth and make room for new trees to grow. So the death of individual trees in the forest is not always cause for alarm. In many cases, it is integral to the continued health of the entire ecosystem.

Death and decay are treated differently in more controlled ecosystems, such as those found in plantations, parks, and urban settings. For those who depend upon certain trees for products or aesthetic value, the priority placed upon healthy individual trees may define their perspective of overall forest health.

Non-native or exotic pests and pathogens are problematic in any ecosystem. These organisms have the ability to eliminate species and permanently alter ecosystems. In the early 1900s, American chestnuts covered 25% of eastern forests, but within a few decades, 3.5 billion of those trees, over 80% of the existing population, were dead from a fungal pathogen that caused chestnut blight. Non-native insects such as the Asian longhorned beetle, emerald ash borer, and hemlock wooly adelgid are also wreaking havoc in the United States. The immense voids created by these insects and diseases might be filled by invasive and exotic plants. Kudzu, Chinese tallow, climbing ferns, cogon grass, and Chinese privet top the list of invasive plants that are changing the ecosystems of the United States.

The situation appears even bleaker if abiotic threats to forests are also considered. Forest fragmentation by roads and development; land loss due to urban encroachment; improper fire management regimes; air pollution from ozone, sulfur dioxide, and nitrous oxides; runoff from concentrated animal feeding operations (CAFOs); and climate change are all factors that can weaken trees and forests.

Many of the problems associated with unhealthy forests originate from human actions, through mismanagement or misconceptions. This can be a source of hope, because while we may have caused these problems, increasing awareness and knowledge and changing our behaviors may help resolve these issues. Educating young people about the significance of healthy forests and the consequences of management activities is essential. Research and management are essential components of maintaining or restoring forest health, but so too is an informed public. Monitoring imported goods for pathogens, managing forests through prompt harvesting and prescribed fire routines, encouraging native vegetation, creating better buffers against abiotic pollutants that we produce, and indeed producing less and conserving more, are important concepts that need to be understood as well as practiced, to ensure the continued health of forests.

Forest health is an important topic for biology, agriculture, current issues, and environmental science classes. There are basic concepts and unanswered questions. There are historic successes, calamities, and current debates. Challenges affect urban and rural residents, private landowners, and public properties. Some dimensions are natural, while others are caused or magnified by people. It is a topic that includes variety and complexity while inviting multiple opinions and new discoveries.

There is no question that forests provide important ecological services and economic resources to Floridians. Similarly, there is no doubt that the health of our forests is at the mercy of how we manage our landscape and make decisions.The activities in this supplement, with the original PLT Guide, help our students rise to these twin challenges.

Using This Material

This handbook is a supplement to Project Learning Tree's (PLT) Pre K-8 Environmental Education Activity Guide. The PLT Guide is a national environmental education resource with 96 engaging activities that help educators introduce trees, forests, and environmental issues to youth. The goal of this supplement is to convey basic concepts of forest health, which of course should build upon a knowledge of trees and forests. Supplementing the national PLT Guide made it possible to focus here on Florida forest insects and pathogens, Florida forest ecosystems, and Florida forest management strategies. You can find out more about Florida's PLT program here: http://sfrc.ufl.edu/plt.

A survey of educators and review of the Next Generation Sunshine State Standards suggested that this material complement the science curriculum in grades 5 and 7. We have selected three basic concepts to help these students understand forest health, and each concept forms one section in this supplement:

Section 1: Forests are ecosystems that are composed of interacting parts. These parts include plants, animals, and abiotic components, such as soil, water, fire, and climate. In this section we identify ten PLT activities that can help teachers introduce forest ecosystems, and we have designed modifications to three PLT activities to help convey concepts that focus specifically on forest ecosystems. We also developed two new activities.

Section 2: Forest insects and tree diseases play important roles in forest health. At low levels, they can improve forest health by removing weakened trees from the system. Anthropogenic factors have the potential to trigger population explosions that can significantly damage forest health and challenge forest managers. A variety of PLT activities discuss forest animals; we identified seven such activities and provide Florida-specific information about insects and pathogens in the modifications provided here. A new game was developed about the disease triangle.

Section 3: Forest management includes the set of tools we can use to protect, maintain, and restore forest health. Six PLT activities are recommended resources to introduce concepts about forest management, and three additional activities are modified in these pages to help teachers focus on the health issues associated with management strategies. An additional two activities were created to supplement the PLT activities.

The document will be most helpful to educators if they have a copy of the PLT Guide; the referenced activities are not duplicated in these pages. Educators can obtain a PLT Guide by participating in a workshop or enrolling in an online training course. Information about both opportunities is available through the Florida Project Learning Tree office at the School of Forest Resources and Conservation at the University of Florida and on their website:http://sfrc.ufl.edu/plt.

Additional information to supplement this material is available at http://www.sfrc.ufl.edu/extension/ee/Curriculum_for_educators.html . This site includes fact sheets, flash cards, photographs, slide presentations, and links to other web sites.

A forest health guide for high school educators is available on EDIS at https://edis.ifas.ufl.edu/fr355

To download this 80-page document, please click on the link above.

These resources have been produced with assistance from the Florida Forest Service (formerly the Florida Division of Forestry), the USDA Forest Service, and the UF/IFAS School of Forest Resources and Conservation.


1. This document is FOR286, one of a series of the School of Forest Resources and Conservation Department, UF/IFAS Extension. Original publication date July 2011. Reviewed August 2017. Visit the EDIS website at https://edis.ifas.ufl.edu.
2. Sarah L. Hicks, graduate assistant; Martha C. Monroe, professor; Geetha S. Iyer, graduate assistant; and Jason A. Smith, assistant professor; School of Forest Resources and Conservation, UF/IFAS Extension, Gainesville, FL 32611.