Remember, when you begin a project that includes the outdoors that careful consideration must be given to existing trees on the site. Some trees are listed (details here) and some are subject to protection orders. Either way, and even if they are not listed or protected individually, it is usually better to work with and save what you have already. Jersey Trees for Life can help identify any issues and help you with legal guidance and management of trees on your property not only during your building project, but at any time.
Visit their website for more information: jerseytreesforlife.org