From an architectural standpoint – indeed, from pretty much any standpoint – Sunningdale is one of the most significant venues in golf. Set in the famous golfing heathland west of London that is also home to the courses at Swinley Forest, The Berkshire and Wentworth, it is one of the first and finest examples of inland architecture. Its courses, the Old and New, were laid out by two pioneering golf architects, respectively Willie Park Jr in 1901 and Harry Colt in 1923. And it was on the Old course that, in 1926, Bobby Jones played his fabled 'perfect' round of 66, made up entirely of threes and fours and requiring 33 putts.

Factor in the additional and welcome pressure that – with an entry criteria of a 12 or below handicap – the membership comprises experienced and high calibre golfers with a keen interest in course layout, and any reticence to change is understandable.

But a century is plenty of time for nature to change the landscape, and for maintenance regimes to completely redefine the style of bunkering. So leaving such important courses alone is a greater sin.

Murray Long was appointed course manager at Sunningdale in 2006, having previously worked at Coombe Hill and been involved first-hand in the well-regarded renovation programme undertaken by Ken Moodie and team at Creative Golf Design. There, as at Sunningdale, the steady ingress of trees had diluted the heathland nature of the course and, along with bunker renovation, a tree removal programme has improved the character of the course.

In architectural circles, trees are often considered to be the enemy, as Long explains: "Trees can inhibit sunlight and airflow and prohibit the development of heather and grasses that provides a desirable heathland character." And as trees grow into the line of play, the strategy of holes can change.

But to many golfers, tree-lined fairways appeal, framing each hole and adding a sense of isolation and maturity. This view is particularly understandable on Sunningdale's Old, and there can be few other courses that are such a pleasure to walk. Every turn seems to offer something new and enticing, a journey through woods and heath that offers immense appeal to golfers, often accompanied by their four-legged companions.

Herein lies the dilemma for Sunningdale; how to reap the benefits of its ideal heathland terrain without losing the character that has evolved over the years. Secretary Stephen Toon explains their first step: "Being acutely aware of the historical importance of our golf courses, we wanted to take a considered, informed and professional approach to any course modifications." With this in mind the club contacted the European Institute of Golf Course Architects to invite its members to register their interest in working with the club. A process of shortlisting and individual discussions followed, until Martin Hawtree was selected as consulting architect and invited to undertake a review of the courses.

Hawtree's extensive experience with the work of Colt no doubt contributed to this choice. It is Colt's hand that is most evident at Sunningdale. In addition to designing the New course, Colt had a significant impact on the early evolution of the Old course during his tenure as secretary, in particular to accommodate the arrival of the Haskell ball, which travelled up to 20 per cent further than the gutty that was in use when Park laid out the course.

As Bruce Critchley put it in GCA (Issue 1, page 22): "Colt saw it as his vocation to bring in angles and bends, slopes and undulations, the soft curves of nature." Colt liked man-made hazards to look natural. Like Hawtree's recent project on Colt's layout at Toronto Golf Club, the natural, rugged styling of the bunkers has disappeared with time, with their edges being smoothed as a result of a century of play and maintenance.

Upon production of a course policy document, the team was completed with the appointment of construction firm MJ Abbott, which had previously worked with Sunningdale on an irrigation project and with Hawtree on bunker work at St George's Hill. The first project to be undertaken by the team – something of a pilot to test the membership's appetite for change – was to stiffen the challenge of the third hole on the Old course, a driveable par four. The green complex had become a bit bland over time, with shallow, featureless bunkers and little in the way of contouring in the surrounds.

Russell Talley, from Hawtree, explains how they introduced additional shaping to the green complex: "Some contouring to the left of the green seemed typical of Colt, so we used this as inspiration for shaping around the green." The bunkers have been deepened and the banks built up, with heather planted to roll over the banks and into the sandflashed faces. Talley adds: "The resulting effect is a sense that the green complex has been tightened up, and the penalty for missing the green is more severe.

With new bunkers front left and right, the tee shot decision between laying up or going for the green requires more thought and the balance between risk and reward has been improved." So strategically the new hole has more to offer, but it has also been visually transformed. A pair of fairway bunkers visible from the tee but rarely in play have been given a makeover, and provide a great taste of what to expect around the green.

Toon explains that the membership embraced the work: "In many cases, the consultative process between architect and membership led to more significant changes than originally discussed." It opened the way for more work, including the famous tenth hole, where fairway bunkers have been repositioned and set at an angle to the line of play, while the greenside bunkers have been given shape and character that Colt would surely approve of.

It is clear that every detail has been given a huge amount of attention by Hawtree. Course manager, club secretary and constructor all testify to his insistence on getting every undulation precisely right. Steve Briggs of MJ Abbott explains: "We worked very closely with Martin to get the contouring exactly how he wanted. Often it would be a case of making small, incremental changes until the desired effect was achieved".

Toon adds that the key to success has been "the high quality of interaction within the team, between architect, constructor and course manager." Perhaps the most striking work at Sunningdale is taking place on the New course. Historic photos – famously of the short fifth hole – show an open backdrop of heath, with just a few copses of trees in the distant background. Over time this area had become heavily wooded, constraining the growth of heather and probably hindering the pace of play as golfers searched for lost balls.

Course manager Murray Long has championed extensive removal of trees throughout the course, and is transforming the landscape back towards its early-twentieth century state. Vistas have been opened up and the heather is already beginning to flourish in cleared areas. Toon believes that the tree removal work on the New "sharpens the contrast between the courses," providing golfers with memorable and different experiences.

In addition to this tree clearance work, significant reshaping has also taken place. The biggest single project has been in the area surrounding the first tee and the eighteenth green. A larger, wider teeing ground has been added to the first so it can serve as a practice teeing ground during the 2008 Women's British Open, and other professional events such as the 2009 Senior Open Championship.

In the area to the left of the eighteenth green, a 'quarry' effect has been created.

Where previously there was a steady slope up towards the clubhouse and green, there is now an area of hollows and mounds covered with rough grasses and heather, providing a much more natural surround. The previously revetted greenside bunker has been transformed to one with Colt characteristics, and two further bunkers have been added in the approach to this par five which introduce a greater element of strategy on a hole that had become less challenging as technology has progressed.

One side-effect of the work to Sunningdale's courses is that some of the bunkers that have not been reconstructed are now conspicuous by their lack of character. But Long's greenkeeping team is handling some of the work in-house, with Abbotts being called upon when the work becomes a little heavier.

Next on the agenda is the sixteenth hole on the Old course, where bunker reshaping work is proposed, in particular to enhance the visibility and severity of the 'necklace' of bunkers short of the green approach. The visual deception offered by these traps will be more convincing and, combined with repositioning of the fairway bunkers, should give the golfer more reason to stop and think before playing their shot.

Assuming the work continues, Sunningdale will further enhance its current position as home to two of the game's premier courses. It is incredibly refreshing to see work that is having such a profound and positive effect on character and challenge, without relying on the addition of yards. Even more so on courses that regularly host golf 's best players.