Alishan — "Mount Ali" — is Taiwan's most-visited national park since the 1920s.
The area has been settled by Taiwanese aborigines since time immemorial, but ethnic Chinese began settling only in the 19th century. Development really took off only when the Japanese completed the Alishan Forest Railway (1912), a remarkable narrow-gauge train originally built for logging the area's giant cedars. By the 1970s, logging had pretty much ended and tourism had become the area's primary earner, and the entire area was declared a "national scenic area" in 2001.
Alishan is not a single mountain, but a range on Taiwan's spine, averaging 2,500 meters in height and with the highest peak Datashan (大塔山) reaching 2,663 meters. Taiwan's highest mountain, Yushan (3,952m) is easily visible from Alishan.
Flora and fauna
Due to its elevation, Alishan's flora are more temperate/alpine than tropical, and the slow transition from bananas and palms to evergreens on the way up is interesting to watch. The dominant feature are giant Taiwanese red cypresses (Chamaecyparis formosensis), some of which have been growing in the area for well over 2,000 years, although most are now managed forests for logging. In spring, crowds flock to view cherry blossoms, while in summer the mountainsides are blanketed with orange montbretia blossoms.
Due to its elevation, Alishan is considerably cooler than the coast, with daytime highs averaging 14-24°C in summer and 5-16°C in winter. Even for a mountain, Alishan's weather is extraordinarily rapidly changing: an average day starts with a cloudless morning, theatrically dense clouds of rolling mist by noon and ends with a lightning storm and torrents of rain before repeating all over the next day. Humidity is always very high, and indeed most surfaces in the park seem to be covered with a layer of luxuriant green moss.
The famous Alishan Mountain Railway narrow-gauge train from Chiayi will not get you all the way to Alishan due to the typhoon damage; it only goes as far as 'Fenchihu'/Fenqihu (奮起湖). Don't miss this trip, especially if you're a train or architecture buff, as the line is largely the same as it was before WW2.
As of January 2017, there is a daily departure from Chiayi at 9:00am. There are extra trains on weekends on holidays, leaving Chiayi at 9:30am and 10:00am. Detailed timetables can be found on . The trip takes 2:20h and costs 384NT$ for the entire route.
Note that trains can be sold out for days in advance, if so you might be better off trying your luck coming downhill. During peak periods like summer and the cherry blossom season trains can get very crowded, so book ahead by calling operator Hungtu Alishan at (05)225-1978, preferably in Chinese, and show up at least 30 min before departure to collect your tickets. Alternatively, there are sometimes "scalpers" standing outside the ticket window selling tickets at-cost, in the hope that you will also book a room in the hotel they work for or if seats are sold out on the train, they still sell standing only tickets (managed to get midweek in cherry blossom season 20 minutes before leaving) and if you're lucky you will get a seat anyway. In Chiayi station, note that the Alishan ticket counter is on the outside of the building, separate from the ordinary TRA counters.
To continue, you will need the Bus (minivan) connecting Fengqihu and Alishan. There are daily departures at 10:30 from Alishan and 14:40 from Fenchihu (on the weekend there are more). These busses can only be reserved on the same day. 
Very comfortable buses from Chiayi to Alishan leave roughly hourly, take just over two hours and cost NT$221 each way. However, the route isn't quite as scenic, with more tea plantations and small villages than cliffs and mountains, but still beautiful. The bus ride can also be quite windy, so be careful if you have motion sickness. Buses stop at Ruili on the way.
As of Oct 2011, there is a direct bus service from Chiayi HSR station to Alishan. Only two buses a day, between 10:00am to 11:30am. Go to the visitors information counter at Chiayi HSR station for more info. Cost is less than NT$300 one way, takes about 2.5 hrs.
Note: The last bus to Alishan from Chaiyi is at 2PM. After that the only way to get to Alishan is by taxi which will cost 1600NT$.
Note: The last bus back to Chiayi from Alishan leaves at 17:10. Buses leave from the 7-11 store across from the tourist information center. Tickets are also purchased inside the 7-11.
From Sun Moon Lake:
There is a daily bus from Sun Moon Lake to Alishan at 8am and 9am, costing 350NT$ and taking 3.5 hours.
Directions for GPS navigation: Alishan station (阿里山火車站)
Whether coming from north or south, take freeway 3 to Chiayi, then change onto road 18 towards Alishan. In the beginning, directions to Alishan on road 18 are well signposted in English, later you just need to head straight until the end of the road. Although it's just about 45km along road 18, you should plan well over an hour to arrive due to steep curves and high elevation (from about sea-level in Chiayi to 2000m in Alishan).
Entry to Alishan costs NT$150 per person if arriving on public transport, NT$200 if arriving by car, charged on arrival. If you show a (Taiwanese) student ID, the cost is NT$100.
Maps in English, Chinese, and other languages are available for free at the Visitors Center.
There is a special train on the Zhushan Line (see below) to catch the sunrise from the top of Zhushan. Tickets for the sunrise train can be bought one day in advance from 13:00 to 16:30 and also on the same day from 30 mins before departure. The departure time depends on the sunrise time (usually 1:30h before sunrise), both are posted outside the ticket office. As of January 2017, tickets are not limited, and if more than one train is required to carry all waiting people up, additional trains will be used. These leave Alishan station 30 minutes after departure of the previous train, so you should show up early to avoid catching one of the later trains that might arrive during or even after sunrise.
The Alishan Forest Railway (in the hills around Alishan township, not to be confused with the Alishan Mountain Railway from Chiayi to Alishan) has three very popular spur lines within the recreation area:
Trails around Alishan are ridiculously well signposted: every intersection of two paths not only has signs in Chinese and English, but a map pinpointing your exact location and all possible routes. You can also pick up an English map from the tourist office. All the main routes are very well maintained, with stairs for steeper sections, guard rails, etc.
Sights around Alishan are signposted in Chinese, English and Japanese, and as you walk around the trails you'll find that nearly every tree of size, age or unusual shape has been dubbed with a fanciful moniker like "Elephant Trunk" or "Three Generation Tree".
The hardcore hiker or sports enthusiast will likely find Alishan's offerings rather too tame, and might do better to go conquer Yushan next door instead.
If you stay overnight in Alishan, you can avoid crowds of tourists who do day trips. You should pretty much have the place to yourself by late afternoon. Wear comfortable shoes with good traction as the steps can be wet and mossy.
You can leave your luggage for free at the Visitors Center (ask the staff) and take it back before 5pm. You can also leave your luggage in sizeable lockers on the 1st floor of Alishan station (same floor for boarding sunrise train). This costs NT$50 for three hours. If you go overtime, you will have to pay extra (another $50 for every 3 hours) to release your bag.
Alishan is famous for all sorts of mountain produce, notably tea (see Drink) and wasabi, as well as carvings and handicrafts made from red cypress. Souvenir shops also sell tasty cookies and pastries flavored with ashitaba (明日葉), a medicinal herb reputed to give long life. The name is Japanese for "tomorrow leaf", as (according to legend) if you pluck a leaf early in the morning, a new one will replace it by the next day.
Stalls selling noodles, rice dishes and basic street food can be found at the Alishan main square, at Jhushan and the Jhoushen Temple.
While you are waiting for the sun to rise, a hot drink from the vendor will warm your hands. Also try the egg crepe, scallion pancakes and French toast. Hot Clear soup with blood rice cake is also available. Hot Sakura flavoured honey in the early morning is great too.
Last but not least, there are two 7/11 stores near the main square, selling instant noodles, microwave meals, fruits, baked goods and a couple of fresh Taiwanese soups.
Alishan's main square has half a dozen largely identical restaurants specializing in hotpot (火鍋), using mountain vegetables and mountain game like deer and wild boar. Most cater mostly to groups and thus offer vast spreads (eg. 10 dishes for $1000), but if you stick to the menu, a "small" pot for two-three goes for around $300.
Alishan is famous for High Mountain Oolong (高山烏龍 Gau-shan wulong) tea and you'll see plenty of plantations on the way up. There are a number of tea shops in the main village that will serve up a pot the traditional way for $200 or so. They will also let you try a number of teas for sale, and this is a good way to pass the evening. But this is with the expectation that you will buy something. Teas are mostly sold in vacuum sealed bags of 150g, and usually will cost between $400-$800, although some can be as high as $3000 for this amount.
Nightlife in any sense is virtually nonexistent, but all restaurants are happy to sell you a beer and you can pick your own poison at the convenience stores.
Most of Alishan's accommodation is clustered around the main Alishan railway station, which is very convenient for eating and shopping, but means a one to two km hike (or short train ride) for visiting the park itself. They can be found in the hotel area, which is behind the visitor center, the stairs down can be found just to the left of the building. While touts meet incoming trains, it is best to reserve the hotels ahead of time, since on weekends (Fri, Sat) and holidays most rooms will be booked almost every day of the summer. Weekday rates are much lower.
A few hotels can be found elsewhere in the park.
Camping is not permitted anywhere within the Alishan Scenic Area. If you have your own car, there are a few campgrounds within striking distance outside the park, notably at Dinghu (頂湖).
There are no dangerous animals or unusual health risks around Alishan. Be prepared for rain at any time and bear in mind that, especially outside summer, it can be quite cold. It is about 10C colder in Alishan than Chiayi.
At the risk of stating the obvious, while the trails are exceptionally well guided during the daytime, there is next to no lighting — so head back when the night starts to fall.
February 2015: A direct bus to Sunmoon Lake leaves at 1pm and 2pm. It costs 332NT$ and takes 3h30. You need to buy your ticket the same day at 9am in the restaurant at the left of the 7/11. You can also choose to arrange for a cab there. A cab from Alishan to Sun Moon Lake is NT$3000 one way.