It has been estimated that before the arrival of William Penn and his Quaker colonists in 1682, up to 90 percent of what is now Pennsylvania was covered with woods: over 31,000 square miles (80,000 km²) of eastern white pine, eastern hemlock, and a mix of hardwoods.
By 1890, Ricketts' land was the largest tract of old-growth forest remaining in the state, and though he made his fortune clearcutting nearly all his land, the forests in the glens of Ricketts Glen State Park were "saved from the lumberman's axe through the foresight of the Ricketts family".
The rough terrain of the glens made it difficult to harvest timber from the area.
Many of the old-growth trees are believed to be over 500 years old, and ring counts on fallen trees have revealed ages of over 900 years.

The forests in and around Ricketts Glen State Park are some of the most extensive in northeastern Pennsylvania, and provide habitat for a wide variety of woodland creatures.
The swampy areas in the park provide a habitat for plants like black gum, yellow birch, cinnamon fern, sphagnum and various sedges.
The old-growth forest in the Glens Natural Area is mostly eastern hemlock, eastern white pine, and oaks, and the park is home to 85 species of shrubs, woody vines, and trees, including seven kinds of conifers.

The streams and lakes of Ricketts are fisheries for many fish species, although fishing is prohibited in the glens area.
In 2009, 4.15 miles (6.68 km) of Kitchen Creek downstream from Waters Meet and all of Phillips Creek were classified as Class A Wild Trout Waters, defined by the Pennsylvania Fish and Boat Commission as "streams which support a population of naturally produced trout of sufficient size and abundance to support a long-term and rewarding sport fishery".

Lake Jean is home to brook trout, brown trout, brown bullhead, and yellow bullhead.
Acid rain with a pH near 3.0 has altered the ecology of the lakes and region; in Lake Jean low pH has decreased the number and quality of insects and plankton at the base of the food chain.
Fish which are acid tolerant are predominant, including fathead minnows, muskellunge, pumpkinseed, walleye, and yellow perch.
Predators like chain pickerel and largemouth bass are relatively few in number, and adult fish appear to grow rapidly but breed comparatively poorly.
Since 1996, the DCNR has added 11 short tons (10.0 t) of powdered lime to the lake each year to make the pH more neutral.
It has been estimated that before the arrival of William Penn and his Quaker colonists in 1682, up to 90 percent of what is now Pennsylvania was covered with woods: over 31,000 square miles (80,000 km²) of eastern white pine, eastern hemlock, and a mix of hardwoods. By 1890, Ricketts' land was the largest tract of old-growth forest remaining in the state, and though he made his fortune clearcutting nearly all his land, the forests in the glens of Ricketts Glen State Park were "saved from the lumberman's axe through the foresight of the Ricketts family". The rough terrain of the glens made it difficult to harvest timber from the area. Many of the old-growth trees are believed to be over 500 years old, and ring counts on fallen trees have revealed ages of over 900 years.
The forests in and around Ricketts Glen State Park are some of the most extensive in northeastern Pennsylvania, and provide habitat for a wide variety of woodland creatures. The swampy areas in the park provide a habitat for plants like black gum, yellow birch, cinnamon fern, sphagnum and various sedges. The old-growth forest in the Glens Natural Area is mostly eastern hemlock, eastern white pine, and oaks, and the park is home to 85 species of shrubs, woody vines, and trees, including seven kinds of conifers.
The streams and lakes of Ricketts are fisheries for many fish species, although fishing is prohibited in the glens area. In 2009, 4.15 miles (6.68 km) of Kitchen Creek downstream from Waters Meet and all of Phillips Creek were classified as Class A Wild Trout Waters, defined by the Pennsylvania Fish and Boat Commission as "streams which support a population of naturally produced trout of sufficient size and abundance to support a long-term and rewarding sport fishery".
Lake Jean is home to brook trout, brown trout, brown bullhead, and yellow bullhead. Acid rain with a pH near 3.0 has altered the ecology of the lakes and region; in Lake Jean low pH has decreased the number and quality of insects and plankton at the base of the food chain. Fish which are acid tolerant are predominant, including fathead minnows, muskellunge, pumpkinseed, walleye, and yellow perch. Predators like chain pickerel and largemouth bass are relatively few in number, and adult fish appear to grow rapidly but breed comparatively poorly. Since 1996, the DCNR has added 11 short tons (10.0 t) of powdered lime to the lake each year to make the pH more neutral.
Ricketts Glen State Park