First we need to think of the application, indeed the purpose of the fencing; for woodland creation, we need to consider deer pressure including deer species and also access to livestock. The visual aspect should also be a consideration, for example the trees will need protecting - would rather look at a field of green tubes for 10 or so years as or a 6ft tall deer fence which may obstruct your view. These are things that only you as the land owner and user can decide. Individual tree guards will protect the trees from browsing but will not prevent trees being pushed over and rubbed by livestock. A high fence around the perimeter of the whole field could be an option as you probably won't see it, being hidden by trees after 3 to 4 years.
If you are happy with tree guards but just need keep livestock out of a new woodland, barbed wire fencing would be suitable for cattle, plane smooth wire suitable for horses and stock-net with plain wire over the top suitable for sheep. I prefer not to use barbed wire unless absolutely necessary as I have seen too many deer caught up in the top strands so will avoid it if at all possible.
Fencing can be erected to meet your budget as well as use and aesthetics; the cheapest is likely to be wire or plastic net, most expensive is usually the more visually appealing for instance oak-pale deer fencing with a myriad of combinations in between.[/et_pb_text][et_pb_image src="https://james-gillies.com/wp-content/uploads/2020/01/REBNvEZg-scaled.jpeg" _builder_version="4.0.9" hover_enabled="0"][/et_pb_image][et_pb_text _builder_version="4.0.9" hover_enabled="0"]
Other fencing options will include wooden post and rail or electric fencing which can be permanent or temporary. Electric fencing works well to exclude larger deer (roe, fallow, sika and red deer), it will need to be checked daily and is not ideal where muntjac deer are a problem as they will push underneath it.
Specification of materials is critically important to ensure stability and longevity of your fencing. Over the past few years there have been many issues relating to longevity of timber fencing, however now have products available with an expected 10 to 20 year life span depending on protective treatment. Always ensure that timber is treated to at least HC4 standard which gives a 15-year guarantee against rotting, assuming it has been installed correctly. The guarantee will not cover labour. If at all possible I would use creosote treated posts as this should give you a 20 year life span. Protection of rails is less critical as they are not in contact with the ground and therefore less liable to decay. Oak fencing could last 50 years or more and will look fantastic - something to show your friends neighbours!
In summary my advice would be to consider what you would prefer to see then look at your budget and work back to a £ per service-year cost.