WISCONSIN—‘Tis the season to deck the halls with boughs of holly. We have spent time planning details for decorating our homes to create a festive atmosphere during the holiday season. While we made sure we picked out the perfect tree, we should also consider how we will dispose of the tree once the holiday season has ended.

One method of disposal—discarding your tree in a forest—may have a hidden danger. Freshly cut trees can bring uninvited guests in the form of invasive species that could infest new areas if they are discarded near other trees. Even if your intention is to create wildlife habitat or let your tree decompose naturally, doing so may end up causing more harm than good.

Christmas trees are most typically pines, spruces or firs, all of which are conifers—also called evergreens—that do not lose their needles in autumn. Evergreens share some common characteristics, including susceptibility to pests.

For example, research published in 2020 suggests that a discarded evergreen, like a Christmas tree, could be capable of infecting other evergreen species with an invasive pest for more than a month. In the study, twigs of eastern hemlock infested with elongate hemlock scale were brought into proximity with 16 different evergreen species. The pest was able to transfer from the dead twigs to a live host for up to 40 days. The study also revealed that some species were more likely to be infested than others. Among the most susceptible were Fraser fir, blue spruce and Virginia pine.

If you’re seeking an environmentally friendly way to dispose of your Christmas tree, here are some options to consider:

• Check with your local municipality to see whether they have a service that chips Christmas trees into mulch for use at community parks or by residents, or any other tree recycling options.

• Contact your state’s wildlife department to see whether they take donated trees to submerge in lakes to create fish habitat.

• Donate your tree to a zoo or animal center that uses them as treats or playthings for animals. There may also be local farms that can use them to feed their goats.

• Check with authorities to see whether they can use your tree to stop beach erosion.

• Check with the National Christmas Tree Association to see what they suggest.