For felling trees there is usually authorization needed, and there is often a compensatory duty.
Nowadays there are many personal safety means to work with a chainsaw: multi-fiber trousers, helmet, face shield, hearing protection, gloves, shoes with steel toe. Use them. The several years without have damaged my hearing permanently and severely. Important: do not work alone, and make clear working agreements. The helper stays out of the reach of the saw and the falling tree.
Please note that the upper quadrant of the tip of the blade when rotating chain is a kickback zone. If you touch an object it kicks the saw upwards.

Forest management:”Where did you work before?”"In the Sahara.”"There are no trees anyway?”"Not anymore!”(JW Besouw)

Determine felling direction
Walk at a sufficient distance around the tree to assess which way the trunk leans, and where most of the weight of the branches is. Do not underestimate the wind. Work if there is (almost) no wind. Especially when there are leaves on the tree. If you count all the leaves together, you get a huge sail! And wind can change within a second a quarter of direction and of strength.
Look where other trees, (power) cables, buildings, fences, watercourses and empty space are. Span at a high tree with uncertain direction of fall or little Safety Area one or more guide ropes. If the tree is not too high you can throw an anchor in. (Yeees, with a rope on it..)
If you attach a rope or chain with a loop or an anchor in the canopy, the fixed point should be on the extension of the rope to the center of the trunk. If it is aside, e.g. on the side of the trunk, or on a branch, the trunk will rotate around its axis, by drawing (when the hinge is (partially) cut through) so that the center of gravity of the tree changes and the direction of fall thus probably too.

For a small tree the helper can push with a long pole at the back (away from any retired saw). This is effective only just before the tree falls, sooner or later not (no longer). With feeling and timing it works.
Avoid: tree felling man!

Do not have endless faith in ropes and chains. A falling tree will break them easily. That makes them dangerous whips that can chop off limbs.

If you fell tall trees, do not mistake in height. It is often difficult to estimate. Agree that they are higher at least 1/3rd to 2x what you think! During felling you let anyone (except the helper) in a radius of 2x the expected felling length around the tree. Certainly not to help to pull. Usually it is not wise to run away from a falling tree. He reaches further than you think, and knocks you down. Walk to the branchless part of the trunk, so you can stand beside. Try to estimate it wisely. Note: the falling crown have some swing and dropping, and the falling bottom side can through the branches spring back up (and down again, and even backwards).

Before you start cutting make room to work and escape freely. Make the trunk branch free, as high as safely possible. Make the foot free from soil and stones. That makes you saw bone. Note that there are no pieces of fence wire or nails in the wood.
Saw on the side where the tree must fall a large wedge just above the ground in the trunk at an angle of about 45°. Books and courses say that you should cut until 1/5th deep into the trunk. I never saw less deep than 1/2nd. Prefer something more. (Except for hollow or rotten wood.) If you want to use to bring down the tree in a desired direction, this directional notch is required. This will bring the main weight above the cavity instead of on the trunk, and you have more control.
Soon you will go around to the back, to saw a few centimeters higher than the front a flat cut (partly) trough the strain. To tear the wood as little as possible when it falls, you make at the same height on the sides a blade deep cut. If the foot is very thick you can saws a notch on the sides too. Not too deep into the core, more straight down. Not too much, because it reduces the control over the felling direction. But so much that the standing part is smaller than the blade.
Then you saw from back to front. Note the effect of the cut. If the opening increases the tree is falling.

If it becomes smaller it goes the wrong way. Hold the saw running to avoid it is pinched. Take it out from the side, and smite two wedges in the back before going on. Or clamp the rope or winch. Leave a few centimeters wooden connection (hinge) at the pivot point (the beard). This is the final direction check before the fall. If you would saw through the tree can turn, e.g. by misjudgment of weight, wind... A falling tree you cannot do change its direction. Do not try to push, (switch off the saw,) get out.

A felling lever is a kind of crowbar to force small trees (up to 20-30 cm in diameter) in the right direction. You press the wide blade of the lever in the middle of the cut to tilt trees over their dead center. Lift with your legs bent and straight back.
Some felling levers also have a hinged tilter to rotate lying trunks.

Pulling with a rope works just before and at the beginning of the fall. And then get out. A wrong falling tree you cannot stop with a rope. Once the tree is falling doesn’t drawing make any sense anymore. We then walked to the trunk, not away from the crown. The smaller trunk is easier to assess and avoid than a high and wide crown.

A hollow tree or one with rotten spots is unpredictable.

If you work in a dense forest, the tree is sometimes standing up among the branches of the surrounding trees. Especially with pines. Often you can simply saw through the trunk. Much of the weight is carried by the branches of the other trees. You can lift the tree a little and run away with it while he’s falling. Even with heavy trees really able. If it fails, or the tree remains hanging, between the others then there is nothing else to do but each time to saw the lower part of the trunk (waist height) so that he every time drops a little deeper and falls. If you need firewood this is not a problem. Otherwise pity of the wood.

Dismantling trees

If the tree is dangerous between buildings, and cannot fall, you have to dismantle it from above. Climb in it (or if possible: use a platform), and each time saw one short piece off and lower it down on a rope. Make sure that you are securely anchored yourself (with a steel cable), and do not cut through that anchoring!
If you use a ladder, you must of course also anchor It.
If you need to climb, use a good handsaw. That works fine, a little slower, but much safer. Make sure that you will be secure.
To cut (with the chainsaw) branches: never saw the height of your body, but above your head and /or on the other side of the trunk (with the stem between your body and the saw).
Switch at every movement or fall of a piece of stem or branch the saw off at once, and let it then rest on the other side of the tree against the trunk while you hold yourself. (There are little chainsaws that you can control with one hand, but a chainsaw is always meant to be used with 2 hands.)

Trunks and branches are always under tension. If you try to cut them in once you have a real chance you saw gets stuck, or the wood is tearing. That's why you saw them first 1/3rd in, and then from the other side. If the pressure comes from the top, you start with this top. Saw as much as possible with the flat side of the blade, not with the point. That is too hot, and that is not good for the quality of the chain and blade.

To saw a trunk lying on the ground for firewood you saw on the desired length of firewood, each time straight. As deep as possible, but without touching the ground. At the bottom the roles all remain so few centimeters stuck together. Trunk and floor are not perfectly straight, not everywhere, so you'll naturally find a place where you can cut the remaining connection through with the top of the blade.
Then roll the half -slotted stem around and saw on every right cut the remaining connections. (An angled cut makes it unnecessarily difficult.)

If you are sawing a thick standing trunk and you go to the other side to saw further or cut a wedge -like in appearance, it can help to see a straight cut line if you stab a twig on the other side in the cut.

With handsaws this will all go also. But slower.

Always try to make a perpendicular cut. That is the shortest route between two points. And so it takes less energy and time. But mostly it ensures minimal friction on the saw, which otherwise can even block. So you save use of extra energy, both with a chainsaw, as with a circular saw, hand saw,...

The stumps excavation: better let the trunk at the stump. That can be used as a lever to pry back and forth. Make the ropes as high as possible in the tree to get the strongest possible leveler power. Dig as many roots free and chop pieces of about 20 cm out between. Otherwise you do not see and feel whether there is another root underneath, and you can’t dig deeper.

In 1927 Andreas Stihl made ​​his ”mobile hand chainsaw”. (But before that, there were already working models.) The first copies were to be operated by two men.

A chain saw is designed to cut fresh wood. In dead, dry wood, they will be much faster blunt.
Any saw you use, sharpen them regularly. This can, for a chainsaw, with a good hand file. Always try to file all the same oriented teeth to the same angles.

Good tools work better. Service the saw. If you get already tired to pull the starter to make to get her on, it is a bad start.
Sharpen the chain regularly. There are good, round little files to. Use the correct diameter, and keep the file for each tooth in the same direction, so that each tooth retains the same angle. Various models file holders help you to keep that angle. (If you saw much a special electric grinding mill is even more interesting.)
You can see from the sawdust if the chain is blunt. Sharp they cut big curls, bone they produces just yet powder of sawdust.

By wear and abrasion the to the rear sloping sawtooth becomes increasingly lower. Therefore, it is important timely to file the just before standing depth limiter also, else the sawtooth has no grip in the timber. With a lower depth limiter it works much faster (if the chain is sharp and the engine is strong enough). Many files holders are designed to reground sawtooth and depth limiter in one go.

There are for chain saws attachments and guides to cut logs at the spot in the forest in planks and beams. For a first straight cut you install conductors (sometimes a kind of ladder). Afterwards the straight plane cutting can be used as a guide. As with a potato peeler. Under Chainsaw milling you find information and videos on the internet.

Storing gasoline

There are convenient anti -spill spouts for gasoline jugs. They are quite expensive, but you never cast off aside tank or hopper, and you cannot overflow the tank by the overfill protection. Worth considering.

Fuels age, physical vapor deposition (thicken) and oxidation by oxygen, temperature and light.
A temperature increase of 10°C will diminish the storage time already half. The most volatiles evaporate first with starting problems as a result.
The German ADAC stored once a few gallons of super leaded gasoline in a basement and took tem 25 years later. The quality turned out to be remarkably good and well suited to drive.
Keep conventional fuels up to three (in favorable conditions six) months in an airtight metal jerrycan.
There are also alternative fuels (Alkylate gasoline) which guarantee a lifetime of at least 2 (up to 10) years. I have heard say that the shelf life of ordinary fuel is limited to 2 or 3 months, because there is mandatory biofuel been added, which corrupts and sours. Whether it is correct?
Diesel has a longer shelf life. Never remove the bottom part out of the barrel. Literally. Flocked down are old fuel particles that can clog the nozzles.
Always use your oldest fuel first, possibly mixed with fresh, and after settling.

Legally you can only store a limited supply (5 l). Sealed and preferably above a tray. Keep it safe!

“We tend to cut down a tree when we need a toothpick.”(Ernst Jünger)