When and where to take in fall foliage in Western Pa.

Despite a stretch of unseasonably hot temperatures this week, autumn’s annual rite soon will start to make its appearance in Southwestern Pennsylvania.

Leaves will begin to change colors by the end of September, though the peak and near-peak for fall leaves in the region won’t come until the weeks of Oct. 8 and Oct. 15, according to a foliage predictor map from SmokyMountains.com.

Pennsylvania forests make for plenty of sights that start in the northern counties and move south. Locally, the green leaves of birch, beech, black gum and oak trees, among others, will turn bright shades of orange, yellow and red.

In 2017, peak time at the state’s highest point — Mt. Davis in Somerset County — came during the first week of October followed by the Laurel Ridge area in Fayette, Somerset and Westmoreland counties, according to reports from the Department of Conservation and Natural Resources, or DCNR.

Areas to the west, including Allegheny County, peaked the week of Oct. 18, 2017, reports said.

What causes fall colors

As nights get longer and cooler, leaves start to change colors, according to a fact sheet from DCNR. With less sunlight available, photosynthesis slows down, causing chlorophyll — which makes the leaves appear green — to stop being produced. The change in weather and sunlight also triggers a process in which tree branches are sealed off, allowing the leaves to drop.

The color of leaves depends on tree species:

• Oak: red, brown or russet

• Hickory and poplar: yellow or golden

• Dogwood: purplish-red

• Beech: light tan

• Sourwood and black tupelo or gum: red

• Maple, depending on species: scarlet, yellow and orange

Other species, such as elms, don’t have any grand exit — their leaves shrivel, turn brown and fall off.

Where to go

There are plenty of places locally to check out fall leaves, from the Laurel Highlands to Allegheny County’s parks. Prime locations listed by the DCNR include:

• Mt. Davis, Somerset County

• Forbes State Forest, which includes Routes 40 in Fayette County and Route 30 in Westmoreland County near Ligonier.

• The Bedford Fall Foliage Festival will be held Oct. 6-14, with more than 400 vendors, kids’ activities and four days of live music on the weekends.

The Laurel Highlands Visitors Bureau has suggestions for fall drives in Fayette and Westmoreland counties. Some of the highlights include:

• Lincoln Highway, or Route 30, from Irwin to Stahlstown.

• Laurel Highlands Scenic Byway, from Ohiopyle to Fallingwater and on to Fort Ligonier.

• Glades Pike, from West Newton to Somerset.

The state visitors bureau has tips on locations here and around Pennsylvania to see leaves, including the Three Rivers Heritage Trail and the Great Allegheny Passage. Outside the region, the Allegheny National Forest, Gettysburg and Presque Isle State Park are options.

West Virginia and Ohio tourism websites have several suggestions for where to best check out fall colors.

Renatta Signorini is a Tribune-Review staff writer. You can contact Renatta at 724-837-5374, rsignorini@tribweb.com or via Twitter @byrenatta.