Living among tall pines and mature trees is one of the things that makes the San Bernardino Mountains such a beautiful place to call home. But when a large tree begins to weaken, the same tree that provides shade, privacy, and mountain character can become a concern, especially when it stands near a home, driveway, road, or utility line.
The difficult part is that hazardous trees don’t always look obviously dangerous from the ground.
Some warning signs are easy to spot, such as a large broken limb hanging over a roof. Others can be much more subtle. A change in the tree’s lean, movement in the soil around its roots, unusual dieback, or decay in the trunk may all be reasons to have a tree evaluated.
Here are seven warning signs mountain homeowners should know.
1. Dead or Falling Branches
An occasional small dead branch isn’t necessarily unusual. Large dead limbs, widespread branch dieback, or branches that are beginning to fall are more concerning.
Pay particular attention to dead limbs located over:
- Homes and roofs
- Decks and patios
- Driveways and parked vehicles
- Roads and walkways
- Frequently used areas of the property
Dead branches can become especially problematic during mountain wind, snow, and storm events.
If a large limb has already broken but remains suspended in the canopy, avoid standing or working beneath it. Hanging branches can shift or fall unexpectedly.
2. A Tree That Has Started Leaning
Not every leaning tree is dangerous.
Trees frequently grow at an angle because of slope, sunlight, competition with neighboring trees, or conditions that existed when the tree was young. A tree that has maintained the same lean for many years may be very different from one that has recently begun leaning.
A new or noticeably increasing lean, however, deserves attention.
Other warning signs around a leaning tree can include:
- Soil lifting or cracking near the base
- Exposed or disturbed roots
- A change in the tree’s position following a storm
- Recent excavation or construction near the roots
A large tree doesn’t have to fall directly onto a house to cause significant damage. On steep mountain properties, its potential fall area may include neighboring properties, roads, vehicles, fences, or other structures downhill.
3. Cracks or Splits in the Trunk
Large cracks in a tree’s trunk or major branches can indicate structural weakness.
One area worth watching is where two large trunks or stems join together. If that union begins separating, cracking, or showing signs of decay, the tree may need professional evaluation.
Homeowners may also notice:
- Deep vertical cracks
- Splitting between major stems
- Previously closed cracks that appear to be widening
- Broken sections following heavy wind or snow
- Areas where the trunk appears hollow or significantly damaged
The presence of a crack does not automatically mean a tree needs to be removed. Its significance depends on the tree, the location and extent of the defect, and what would be affected if part of the tree failed.
4. Significant Decay, Cavities, or Fungal Growth
Trees can survive for years with cavities, old wounds, and some degree of decay. That means a hollow area or mushroom on a tree does not automatically mean the tree is about to fall.
However, significant decay can weaken the wood that supports the tree.
Watch for changes such as:
- Large cavities in the trunk
- Soft, crumbling, or visibly decayed wood
- Extensive bark loss
- Fungal fruiting bodies growing from the trunk or base
- Areas of the trunk that appear substantially hollow
Fungal growth near a tree’s base can sometimes be associated with decay affecting the trunk or root system, although identifying the significance usually requires more than simply seeing a mushroom.
If you’re uncertain, this is a good example of something worth photographing and showing to a knowledgeable tree professional.
5. Root Damage or Movement Around the Base
A tree’s root system is responsible for far more than absorbing water. It also helps anchor an enormous structure into the ground.
Root problems can therefore become structural problems.
Look around the base of a questionable tree for:
- Soil that appears to be lifting
- New cracks or movement in the ground
- Large damaged or severed roots
- Significant erosion around the root system
- Recent trenching, excavation, grading, or construction near the tree
This can be particularly important on steep mountain lots, where soil conditions, erosion, construction, and slope can complicate what is happening below ground.
If a tree has recently begun leaning and the soil or root area appears to be moving, keep people away from the potential fall area and have the situation evaluated promptly.
6. Storm, Wind, or Snow Damage
Mountain weather can put tremendous mechanical stress on trees.
High winds can break limbs or damage trunks. Heavy snow can load branches until they split. Storms can also expose weaknesses that existed long before the weather event occurred.
After significant weather, look for:
- Broken or hanging branches
- Split trunks
- Broken tree tops
- Newly leaning trees
- Fresh cracks
- Uprooting or soil movement
- Large branches lodged in neighboring trees
Some storm damage can be difficult to see from the ground, particularly in tall trees.
Never attempt to remove large hanging limbs or climb a storm-damaged tree unless you are trained and properly equipped to do so. Damaged trees can behave unpredictably when branches, trunks, and surrounding trees are under tension.
7. A Dead or Declining Tree Is Within Striking Distance of Something Important
The condition of a tree is only part of the equation.
What is around the tree matters too.
A declining tree deep in an unused portion of a large property presents a very different situation from a similar tree standing beside a bedroom, driveway, road, or neighboring home.
When looking at a questionable tree, consider what could potentially be affected if the tree or a large portion of it if it failed.
That might include:
- Your home
- A neighboring home
- Vehicles
- Roads
- Utility lines
- Propane tanks
- Decks or other structures
- Areas where people or pets regularly spend time
The combination of a significant tree defect and an important potential target is one reason professional tree-risk evaluations consider more than simply whether a tree looks healthy or unhealthy.
Tree Hazards Can Be Different in the San Bernardino Mountains
Tree work in the mountains is different from tree work on a typical suburban lot.
Properties throughout communities such as Crestline, Lake Arrowhead, Running Springs, and Big Bear may include steep terrain, large mature conifers, narrow roads, limited equipment access, nearby structures, and utility lines running through heavily wooded areas.
Mountain trees also experience environmental stresses that aren’t equally common everywhere.
These can include:
- Snow and ice loads
- Strong mountain winds
- Drought stress
- Wildfire conditions
- Bark beetles and other pests
- Erosion and slope conditions
- Storm damage
Even access can change the complexity of a project. A tree located on a flat, open lot may present a completely different removal challenge from a similar-sized tree growing on a steep slope between a house and a narrow mountain road.
That’s why evaluating the tree and its surroundings is important.
Does a Warning Sign Mean the Tree Has to Be Removed?
No.
Finding one of these warning signs does not automatically mean a tree should come down.
Depending on the situation, a tree professional may recommend monitoring the tree, removing a damaged branch, pruning to address a particular concern, obtaining further evaluation, or removing the tree when the risk cannot reasonably be addressed another way.
The purpose of recognizing warning signs isn’t to diagnose a tree from the internet.
It’s to know when something may deserve a closer look.
What Should You Do If You’re Concerned About a Tree?
Start by observing the tree from a safe location.
If possible, take several clear photos showing:
- The entire tree
- The base and surrounding soil
- Any visible cracks or damaged areas
- Dead or broken branches
- The tree’s proximity to your home or other structures
Those photos can make it much easier to explain what you’re seeing when requesting an estimate or evaluation.
If a tree or branch presents an immediate danger to people, an occupied structure, a roadway, or a power line, stay clear of the area and contact the appropriate emergency service or utility provider. Mountain Tree Quotes is not an emergency-response service.
Concerned About a Tree on Your Property?
If you’ve noticed a leaning tree, dead branches, storm damage, decay, or another potential problem, you don’t have to figure out the next step by yourself.
Tell Mountain Tree Quotes a little about the tree, your property, and what you’re seeing. You can also upload photos with your request.
We’ll help connect you with one participating local tree-service professional at a time who serves your mountain community and handles the type of work you need. This means that only one professional will receive your request for work, rather than your number being sent out to anyone and everyone on the mountain.