A disturbance is any kind of event that kills or gets rid of existing vegetation in an ecosystem. A classic example of a disturbance is a forest fire. A forest fire will kill trees and other vegetation by burning through the bark which prevents nutrients and water from reaching new growth. There are however many types of disturbances. Some natural types include blowdowns from windstorms, volcanic eruptions, overbrowsing by wildlife, insect infestation, disease, flooding and severe drought. There are also man made disturbances such as plowing the soil, logging, brush clearing and mowing. Managing disturbances is an important part of maintaining a property for wild game and the specific techniques you use will depend on many factors such as climate, local wildlife species, types of existing vegetation and management goals.
Climate is one of the most important things to consider when managing disturbance. In general when managing a property for wild game it is best aim for a mosaic of savanna and shrubland habitat. This will consist of open meadow type areas, and scattered trees and shrubs, the exact configuration depending on the game species you're managing for. To create this type of habitat you will have to use certain disturbances such as clearing brush, coppice, and possibly mowing. But this will largely depend on your local climates. On one extreme you have very wet areas that generally succeed to dense climax forests. In these areas you will generally have to create new disturbances quite often due to the fast establishment and growth of trees. This is especially true if your region is already covered in dense forest which will provide an abundant source of new seeds. In these types of areas a clearcut forest can reestablish and start it's growth very quickly turning into a dense brushy stand of new growth in just a few years. On the other extreme is a dry barren desert type area where you will want to almost eliminate any disturbances due to the very slow growth of new trees. On these types of sites you will have to baby your plantings by watering them regularly and providing mulch at least until they are more established. Creating a disturbance in this environment would be counterproductive and set you back too far in succession. In this type of climate you will lean towards more inputs. More seeds, more watering, more mulch, more earthworks, and more work in general just to get your plants established. Where as in very wet areas you will be aiming more for taking away vegetation because of frequent vigorous growth. Another consequence of this is that you will have to closely manage browsing pressure. So for drier properties you would want lower browsing pressure due to the fragility of the habitat so in general this would mean lower game populations especially with browsing species such as deer. On very wet sites you could get away with higher populations and more browsing pressure due to the more vigorous regrowth rate of the vegetation. If you want the least amount of work i would aim towards a middle ground for a climate that is only moderately wet, but also may have occasional dry spells. These types usually will also resemble the habitat your trying to create generally supporting a savanna and/or open woodland/ shrubland type environment. Although for the highest game densities a wetter environment may be better.
Most properties will not be homogeneous, but will instead consist of several microclimates. These include dry uplands, wet bottoms, cooler and wetter north facing slopes and warmer drier south facing slopes. Your management of disturbance on your property will be different for these different microclimates. In general for drier upland areas and drier south facing slopes I would recommend creating less disturbance than on other areas of your property. This is because these areas are generally harder to get vegetation established. If you create too much disturbance in this area it might take a long time before you can reestablish a significant amount of vegetation. On wetter areas however such as bottoms and on north facing slopes you can generally get away with more disturbances and if you do too much it is more likely to grow back quickly.
The way you manage disturbance will also be dependent on the game species you are managing on your property. For browsing species such as deer you will want a majority of the vegetation to be within their reach so they can make use of the food on your property. This will mean you will have to periodically cut trees and shrubs that have grown too high above the browse line. Most browse species will be able to be cut just above the ground level and should resprout from the root crown. This technique is called coppicing and is a way to manage most hardwood trees and shrubs. Conifers will generally be killed if this is used unless there is still a growing tip left on the foliage, but I would not recommend coppicing conifers as they will most likely die. Other trees I would not coppice are nut and fruit trees, especially large healthy specimens that are producing a large amount of food. Other possible techniques such pollarding and hinge cutting may also be used depending on the existing vegetation and your overall management goals.
For species more adapted to grazing such as elk you will want to have a larger proportion of open meadow type habitats with grass and forbs. For these areas you may need to clear brush or mow occasionally if woody shrubs and trees start to encroach. Another possible option in these areas, especially on larger properties might be to do a controlled burn. This if done right and in a safe manner could drastically improve large open areas with relatively little work. But again make sure you do a ton of research and use professional help because of the dangerous potential for the fire to get out of control.
The way you manage disturbance on your property is very important to developing good wild game habitat. Too much disturbance can destroy too much of the vegetation that is used for food and cover, but not enough could shade out plants at browse height because of shade from tall trees. You will want to study and observe your property to find the right balance so you can create the optimum habitat for the game animals on your property.