If you treat them properly, trees can shade your home, beautify your property, and even save you on energy costs. But disease, pests, or extreme weather can harm even the strongest oaks. And even healthy trees need a little branch care in the form of regular pruning or occasional checkups.

To keep your trees in shape or get rid of dying trees, you’ll likely need professional advice, skill and labor. To help you find that help, the nonprofit consumer group Delaware Valley Consumers’ Checkbook surveyed its members and other consumers about their experiences with tree services in the area. Through October 5, Checkbook Inquirer is offering free access to its reviews of tree services in the area. Readers via Checkbook.org/inquirer/trees.

You don’t have to be an expert to spot many potential tree problems. Inspect your trees several times a year for the following:

Other reasons for tree work include preventing your home or power or other utility lines from being endangered by rubbing or dangerously overhanging branches, allowing light and air to reach your home, garden or lawn more easily, and protecting foundations and drainage systems from encroaching roots.

In many cases, the problem and solution are obvious – for example, removing certain branches. However, sometimes trees are difficult to diagnose and treat. In such cases, you need expert advice.

But don’t assume that all tree service company evaluators can determine what’s wrong and prescribe the right treatment. Checkbook’s evaluation of local tree service providers found wide variation among companies in the quality of advice and work performed. Although several companies in the area rank quite well for the quality of their work, the news isn’t all good. In addition to complaints about poor customer service from companies with bad reviews, customers often complained about overpriced services, poor results, and damage to their property from careless, untrained workers.

If you need tree services, it’s best to get multiple opinions. Invite representatives from several companies to your home to provide estimates. Ask them to explain what they plan to do and why.

In addition to multiple opinions, you also get price comparisons. Checkbook’s undercover shoppers found significant variation in prices for tree services. For example, to remove a 45-foot oak tree, including removal of all wood and debris and sanding the stump, companies quoted Checkbook’s undercover shoppers prices ranging from $1,933 to $3,340. To remove a 60-foot elm tree, sand the stump and remove all debris, quotes ranged from $2,347 to $4,480.

Typically, you don’t have to be home when bidders look at the job – but include a detailed description of the job in a written contract, specifying who will clean up afterward, haul away debris and wood, and remove the stump. If it’s not in writing, it’s unlikely to get done. No-shows are common, so call more companies than you need to make sure you get enough bids to make a smart decision.

If a job can wait, consider having the work done during the winter when contractors are less busy and there is less debris to haul away.

Check to see if a company’s liability and workers’ compensation insurance is current. Ask to see proof of insurance and call the company’s insurance carrier to verify. This is a serious issue because powerful equipment, heavy branches and trunks, great heights, and proximity to power lines make tree work dangerous.

Ask about the company’s payment terms to see how much of the total cost is due upon completion of the job or later. Paying after the job is completed gives you the opportunity to ensure that the job is done properly and on time.

If you need expert advice and help with tree care rather than simply removing dead trees, look for certification through the American Society of Consulting Arborists (www.asca-consultants.org) or the International Society of Arboriculture (www.isa-arbor.com). Certification through one of these organizations indicates that the arborist has a degree in arboriculture, several years of professional experience, and has passed a difficult exam.

Delaware Valley Consumers’ Checkbook Magazine and Checkbook.org is a nonprofit organization with a mission to help consumers get the best service and lowest prices. We are consumer-supported and do not take money from the service providers we review.