A little later, a sign directed us to the footpath leading up through the dry sclerophyll forest to the tower itself - first angling across past orange flowering bitter peas and purple-tinged hopbush, then taking on the steep slope directly on a narrow paved path. Despite the cool air, jackets quickly came off for this climb.

It was time for another variant - the official route down Black Mountain doubled back into the dry forest on the northern slopes and then took a long circuitous route down on the west. Our route was more direct, following a gravel track down a south-eastern spur to a series of look-outs that gave different perspectives of the lake and city, framed by the forest.

To our left, a bike path headed out from Civic and we joined it briefly to pass under the the looping roads of the Glenloch Interchange and reach the broad grassy woodland of Aranda Bushland, with its, rare for this region, snowgums. Ahead lay one more underpass, which took us away form the bikepath and into the magnificent dappled shade of an 80-year old cork oak forest.

Planted for commercial production and last harvested for cork in 2001, it is now a beautiful part of the new National Arboretum. It was great walking beneath the dappled shade of the canopy, admiring the grey-fissured texture of old bark and rich brown roughness of the new bark. Only the hum of traffic from the nearby interchange stopped this from being tranquil perfection.

Leaving the mature oaks, we began to pass by new plantings of the arboretum - Chilean monkey-puzzle trees, flowering dogwoods and horse chestnuts - before passing up through an old stand of Himalayan cedar to a point where we could look over the extensive plantings of trees from all over the world - some already a few metres tall, others still protected by their pink plastic shelters.

The National Arboretum, officially opened in February 2013, contains 104 different "forests" of native and exotic trees, many of which are endangered or symbolic species. Complemented by a superb timber built visitors centre, pavilion and amphitheatre, amazing kids playground and hilltop sculptures, with some of the best views in Canberra, walking through the arboretum has been one of the highlights of this trail. The forests may be small now, but we are looking forward to watching them grow and seeing the landscape change as they do.

Site of the National Arboretum ( imagine how this will change in time as the forests grow)

After climbing (straight) up a curious zig-zagging pathway that seems to be some sort of gigantic landscape artwork, we had a slow lunch break looking out over the lake and hills of Canberra from the Visitor Centre deck (PS don't miss the National Bonsai Collection - some of the bonsaied native plants are superb).

Black Mountain Tower and the Vistor Centre

The cool westerly wind was strengthening, so we continued our climb up past the Saharan cypress to Dairy Farmers Hill, bare-topped but for several large Aleppo pines and a wonderful scrap metal sculpture of a wedge-tailed eagle on its nest. With panoramic views in every direction, it was hard to understand why the official trail route did not pass by here.

It would not be a Canberra walk if there were not a section of radiata pine - until the fires, which burst from the surrounding pine forests to destroy 500 houses, we loved them as places to stroll, jog, collect mushrooms and walk the dog. Now they are mostly gone and the near city landscape has changed for ever - hills are open-topped and new towns, such as Molonglo, are springing up in their place. We are much more ambivalent about pine forests now.

Descending out of the pines, we reached the Molonglo River, crossing it on a concrete bridge that held back the debris of floods past to reach a bike path on the far side. This bridge is called the Molongo Valley Interceptor Sewer Bridge, but you really don't want to know that. The route through this whole area is fairly fluid at the moment as all to the west, the land has been fenced and cleared for the development of new roads, infrastructure, pondage and houses in the new town of Molonglo. One day the Centenary Trail will pass through this region, but not today. We skirted by the metal fencing on a brand new bike path to pass beneath a bridge on the Cotter Road and reach the suburb of Holder.

Once again, we had reached a bus route and it seemed a good place to stop for the day - the no. 28 bus is not all that frequent, but it was a pleasant spot to rest up as we waited. It had been a day of highlights on the trail and I felt more convinced that it was showcasing the best natural features of the nations' capital.

Some days you just don't feel like walking all day - today was one of them. The choice was 24km all the way to Tuggeranong or 11km to Kambah - there was no bus stop in between. An easy stroll in the morning seemed a much better idea and, as the fair Nello had to mind the grand-daughters today, I got a lift with her back to my starting point at Holder. The excursion would be even quicker.

Thus I found myself wandering westward along a grassy track between the houses of Holder and the new Stromlo Village. This was pretty much a transit stage, but when I turned south to walk beside Eucumbene Drive and began to notice the new contemporary-styled architecture of houses on the left and the open grasslands on the right, it became a stage of reflection. A bit over ten years ago, the houses were all 80s vintage architecture and the west side of the street was at the edge of a dense and mature pine forest. Then came that fateful day of the fire that Canberra will never forget - January 18, 2003, and Eucumbene Street was the first to bear the brunt of the firestorm. Imagine the sky turning black with thick acrid smoke and the roar of the bushfire, as it approached with the speed and noise of a freight train, the 20m pines exploding into flames and the rain of burning embers and fireballs, driven across the narrow strip of bitumen by the fire-generated winds to envelop the houses opposite and drive deep into the heart of these western suburbs. I can't - that day when over 500 houses were destroyed is simply unimaginable.

On reaching the entry to the Nature Park, I climbed steeply up a firetrail to join the perimeter firetrail that meandered around the ridge between houses and grassy woodland slopes. The views over the suburbs of Weston Creek were already opening up and were even better when I made my first track variant and climbed the steps to Cooleman Trig. Out to the west, the green grassy paddocks led my gaze towards the blue horizons of the Tidbinbilla and Brindabella Ranges. These paddocks were once part of the land settled by the fair Nello's ancestors, long before the city of Canberra existed - perhaps that is partly why we liked coming out here so much.

The summit of Arawang

As in past days, the wind began to pick up and, for the first time, high cloud was drifting in. I descended Arawang on the steep rock footpath on its eastern face to rejoin the official track where it spilled out from the Nature Park and on to Namatjira Drive. Here a bike path followed the road south and past the Kambah horse paddocks.

It was the start of another transition stage, but a short one for today, as I headed down the grassy verge of the road leading to Kambah Pool and stopped at bus shelter to wait for the No. 60 bus. Each day, I have wondered whether I would still enjoy the walking and each day I have for different reasons. Today was a trip down memory lane.

I didn't walk yesterday. With winds of 60 kph gusting to 90, it seemed like a good day to stay at home and catch up with a few jobs. The frontal system blew through overnight and this morning was perfect, still air and blue sky, so after yet another bus trip, I found myself heading off down the Kambah Pool Road from the Barritt St bus stop.

This was a transition stage, but as I wandered down the broad grassy verge, between manicured golf course and the forested slopes of McQuoid Hill, I found myself enjoying it. I even found a couple of golf balls out in the long grass and threw them to a chap on the green of the par 4 second - he said that he probably hit them there last week. A trio of horse riders were also out enjoying the morning sun.

Ahead I could see the metre-wide scraping that I recognised as the new track, now somewhat overgrown (which is not a criticism, as I much prefer to walk on track like this than something that is over-engineered, but is it written in the Trackmakers Manual that tracks should always meander even when they don't have to?).

Suburbia was left behind, as the track took me down the road and directly towards the rugged Bullen Range backing the Murrumbidgee River. It was heading to a well-known walking track along the Murrumbidgee Corridor and one of the feature sections of this centenary trail. I reached the head of this track, turned east and followed it through the shrubby bushland that sloped down to the river. For a while, I meandered along, looking out at the eucalypt and wattle covered slopes of the Bullen Range opposite and listening to the twitters and whistles of unseen birds. This river corridor is a migration route for many species of small bird and its was full of them today.

The walking track here has been "upgraded" for the new centenary trail (which is planning-speak for made suitable for cyclists) and a couple of kilometres along, I reached a stage where a new route had been cut to work around a couple of gullies. However, I also noticed that the old foot-track had been ripped up at that point. It seemed fair enough to the give cyclists a new route but at the expense of walkers? I knew this bit of track - it descended into a couple of steep little gullies to approach the river - in fact, a small detour takes you to a lovely spot for a break and relax on the river, the only access point in this part. It was too nice a section to miss, so I headed across the ploughed up piste to reach intact foot track and continue on the "old" route. The river was lovely.

Heading on, the foot track climbed to rejoin the new trail just before the classic viewpoint of Red Rocks Gorge - a narrowing of the valley where the Murrumbidgee has cut its way through the landscape to expose sheer walls of orange-red metamorphic rock. A few workmen were here finishing off a brand-new metal viewing platform and putting in some stone steps to it - they assured me all would be ready before the trail was officially opened next week-end (October 27). The views from the platform both up and down the river were as impressive as always.

Crossing the next ridge, I could see the a big sandy bend in the river and the distant red rooves of the Tuggeranong Town Centre on the hilltop behind - I was approaching civilisation again. However, it was time for another detour. My stomach told me it was lunch and I knew of a nice shady eucalypt down near the river that overlooked the water and sandy beach. I followed the fenceline down, walked through the rusted old gate, found my tree and enjoyed both the tranquility and the sandwiches.

At this point the Tuggeranong Creek flows down into the Murrumbidgee and the official trail does a big loop to cross it on a small bridge further upstream. However, there is a foot-crossing that saves a bit of walking, so after lunch, I rejoined the trail briefly but then followed the sign to where a foot track descended to the creek and crossed it on a long rock rib. Several kangaroos watched nonchalantly as I passed. There are often big mobs in this area and, judging from the number of active burrows, there is also a big population of wombats.

Once on the other side, I followed the track back towards the river, passing through a massive infestation of St John's wort to reach an old stone wall built by the early settlers (at the end of this wall there is another nice riverside lunch-stop beneath the shade of a big casuarina).

A casuarina lined section of the Murrumbidgee

From here I stayed with the official track, climbing up through the grassy woodland, using my GPS (signage should be in place now) to reach the buildings of the Tuggeranong Town Centre. The centre is on the west bank of Lake Tuggeranong and has a lovely foreshore and parkland, so why does the official route go down the main street? I headed for the shore to enjoy the lake, the waterbirds and a cup of coffee.

Eventually though, I had to cross it and join the bike path that led up a parkland spine passing through the suburbs of Tuggeranong. At first the walking was pleasant, alongside a reed- and casuarina-lined pondage, but after that had passed it turned into a bit of a trudge, and a fast trudge at that as I realised the bus would soon be pulling up at the Gowrie shops. I left the bike path and took what seemed a shorter route by footpath and street - it probably made no difference, but in the end I made the shops in time!

Today, more than any other confirmed my suspicion that this trail is a little bit cyclocentric and highlighted the difficulties of finding the right balance for a multi-usage track. There are definitely times when bike-rider and walker must diverge for both to get the most out of the trail and I suspect that, in time, these variants will become quasi-official.

The last day on the trail had arrived and I felt keen to complete it as the fair Nello dropped me off at the starting point in suburban Gowrie. She was on her way to the gym and offered me a lift - no point being a zealot about using public transport. As such, it was my earliest start and the air was still quite crisp as I set off down the bike path and into the Fadden Pines. This remnant of an old pine plantation had been left as a picnic and recreation area for the local residents and it was pleasant strolling beneath the dark canopy of these big old trees.

The bike path led me through an underpass and back into residential houses, though in typical Canberra fashion, it followed a broad greenbelt of parkland and playground that divided the suburb. I was quite enjoying the walk and came to the conclusion that it is best to walk these more urban sections of the trail in the morning when the mind is not pre-occupied with the thought of that cold beer at the end of the day.

The greenbelt gradually narrowed, funnelling me out to the gate of the Canberra Nature Park - Wanniassa Hills Section. This is another lovely area that offers woodland and open ridge tops with expansive views over the Tuggeranong Valley. However, and I suspect in deference to cyclists, the official trail skirted by and onwards on a flatter route - it was time for another variant, the first part of which was a gravel road that curved easily up to a large water tank.

From here, a narrow and at times, faint, footpath climbed up the grassy slopes to reach the tree-covered ridgeline. It was while climbing up that I first noticed the haziness in the sky and it soon became obvious what it was - smoke drifting down from the horrific bushfires in the Blue Mountains, some 200km to the north, was creating a palid pall over the cloudless sky of Canberra.

Smoke haze from the Blue Mountains bushfires

The flora of the ridge, however, provided the distraction needed - yes, the ubiquitous St John's wort was omnipresent and would soon carpet the open hillside in yellow and yes, there were purple patches of Paterson's curse, but these weeds apart, golden everlastings were flowering in abundance and, for the first time on the trail, I spotted the grail of plants, an orchid - a small cluster of donkey orchids to be precise.

Purple haze of Paterson's Curse

Woden town centre almost hazed out

I wandered from woodland to open ridge, with views out to the hazy east and south across the rooves of Fadden, to reach the short detour to the trig of Mt Wanniassa. The smoky haze had created an opaque prism and distant features faded into obscurity, but it was still a great spot to sit and contemplate my surrounds to the intermittent songs of the local bushbirds.

This was another variation, as the official route continued around base of the ridge, but a ridge has views and that is where the walker should be.

Overlooking smoky Woden from Isaacs Ridge

On reaching the crest, the dirt access road followed a fenceline up and down along its spine, with colour-washed views out towards the suburbs of Woden and Mt Taylor and eastwards across the Mugga Hills. The haze was getting thicker and I could faintly smell its smokiness. Even the kookaburra found it no laughing matter. On the opposite side of the fence, there was virtually a monoculture of St John's wort - at least it was outcompeting the Paterson's Curse.

Eventually, the gravel road turned to descend sharply into the pine forest and pick up the banked perimeter track at its base. I was back on the official track, though not for long. It led back into open eucalypt woodland at the back of the houses of O'Malley and then continued on to do a long loop to reach Red Hill via the Hindmarsh Drive / Mugga Way traffic lights. There is a much shorter route for the adventurous walker, one also used by participants in the Sri Chinmoy Triathlons. In fact the pale blue markings they put out for their upcoming 100km Centenary Trail Run helped guide me along the footpaths and gravel tracks through the box-gum woodlands (and wort lands) behind O'Malley.

St John's wort jungle

Woodllands in front of Mt Mugga Mugga

They brought me out to a pretty reed-lined pondage just to the north of busy Hindmarsh Drive, a good lunch spot, before pushing on to my objective - the twin storm water pipes beneath this busy road.

Still, there was time for a coffee at the iconic Red Hill Restaurant, site of many a marriage proposal or celebration in the early days of the city, before descending down the steep red earth track to suburbia.

All that was left was a stroll down the broad eucalypt-lined boulevard of Melbourne Avenue, directly towards Capital Hill, where I wandered through the parliamentary gardens. It was good way to finish, with the regular glimpses of the aluminium flagpole, the world's biggest trig, dominating the parliament and the hill.

The flagpole - rising majestically above the trees

Sleepy Melbourne Avenue

A walk through the Parliament gardens

The back door of Parliament House

End of the trail - the Federation Stone and Parliament House

Reaching the front of the parliament building, one small task remained and that was to wander over to a small brown button on the lawns in front - the Federation Stone. Here, in 2013, Canberra was officially named and its history as the capital of Australia began. One hundred years on, it is the appropriate place for this Centenary Trail, which show-cases the delights - urban, natural and rural - of the bush capital, to end.

Happy 100th birthday, Canberra!!