Ecological aspects of distribution
According to the Flora of Ryukyu [18], Fukugi trees are widely planted as windbreaks on the Ryukyu islands. Old growth Fukugi trees exist prevalently around residences in traditional villages in Okinawa Prefecture, Japan. Fukugi tree dimensions in the survey sites are presented in Table 1. It is considered that such a rural landscape with planted Fukugi trees, and other trees as windbreaks, was designed based on the Fengshui concept in the then Ryukyu Kingdom, around 300 years ago. In some villages, around 70% of all the houses were surrounded by Fukugi trees. In Bise village, north of Okinawa Island, around 10,000 Fukugi trees were counted [39], among which 1,075 Fukugi trees were estimated to be older than 100 years [3]. On Tonaki Island, an isolated small island near Okinawa Island, we counted a total of 7,700 Fukugi trees, among which around 1,000 trees were older than 100 years (Fig. 2). There are other several villages in mainland Okinawa and its nearby isolated islands with around 1,000 Fukugi trees older than 100 years [3].
Our field surveys on the islands revealed that Fukugi trees primarily existed as homestead windbreaks on the Amami Islands, Okinoerabu, and further south on the islands in Okinawa Prefecture. On Okinoerabu’s more northern islands, Fukugi trees were sparsely distributed as windbreaks [3]. Banyan trees (Ficus microcarpa) were commonly found as windbreaks and landscaping trees [3].
In addition to the planted Fukugi trees, some naturally generated trees were also found on the hill slopes of remote islands, such as Iriomote Island [18], Yonaguni Island, and islands north of Okinawa Island. However, natural Fukugi trees are usually small in size and sparsely distributed in coastal areas or uphill slopes behind village settlements. Outside of Japan, old-growth Fukugi trees that were planted were only found in Taiwan. Fukugi trees planted in 1901 as landscaping trees were found in Kangting National Park, where the largest tree had a DBH of 61 cm and was 15 m tall.
G. subelliptica originated in Batanes, the Philippines [19]; however, in these islands, we did not find Fukugi trees used as homestead windbreaks or close to human settlements or developed areas. The scientific name of Fukugi, Garcinia subelliptica, is named after Laurent Garcin, an 18th century French botanist, who first collected specimens of this species from Batanes, the Philippines. In 1908, Merrill [20] reported that one tree had a trunk 35 cm in diameter, with yellowish branchlets growing in thickets along the Philippine seashore. In Basco, the capital city of the province of Batanes, Podocarpus macrophyllus trees were planted in homestead windbreaks. We could not find any Fukugi trees in the coastal areas on the island of Batanes. However, we spent only four days in Batanes, and it is possible that G. subelliptica may have become extinct in Batanes Island.
Table 1. The number of remnant Fukugi trees in survey sites
|
|
|
Number of Remnant Fukugi Trees at each estimated year range
|
Estimated age of Biggest tree (yrs)
|
Mean Tree Height (cm)
|
Mean DBH (cm)
|
Survey date
|
Total
|
≧ 300 yrs
|
250~299 yrs
|
200~249 yrs
|
150~199 yrs
|
100~149 yrs
|
50~99 yrs
|
0~49 yrs
|
|
|
|
|
Motobu Town
|
Bise(1)
|
1,075
|
1
|
17
|
89
|
360
|
609
|
|
|
300
|
994*2
|
38.5
|
Aug-2008
|
Tonaki Village
|
Tonaki Isl. (1)
|
965
|
0
|
2
|
10
|
111
|
842
|
|
|
268
|
842*2
|
31.13
|
Aug-2009
|
|
Tonaki Isl. (2)
|
7708
|
0
|
2
|
10
|
111
|
842
|
4918
|
1825
|
268
|
617
|
17.28
|
Oct-2009
|
Nakijin Village
|
Imadomari (1)
|
1,293
|
0
|
15
|
85
|
307
|
886
|
|
|
294
|
900
|
35.18
|
Jun-2009
|
Aguni Isl.
|
East & West(1)
|
2,561
|
0
|
16
|
82
|
486
|
1,977
|
|
|
296
|
723
|
33.17
|
Mar-2009
|
Hama(1)
|
500
|
0
|
3
|
6
|
55
|
436
|
|
|
281
|
713
|
31.27
|
Apr-2009
|
Miyako city
|
Tarama Island, shiogawa hamlet(1)
|
1,089
|
0
|
1
|
8
|
157
|
923
|
|
|
257
|
1010
|
32.1
|
Aug-2010
|
Miyako city
|
Tarama Island, Nakashiji hamlet(1)
|
1,529
|
0
|
1
|
17
|
240
|
1334
|
|
|
262
|
1030
|
32.2
|
Aug-2010
|
Taketomi town
|
Taketomi Island(2)
|
1,183
|
1
|
13
|
50
|
143
|
298
|
255
|
423
|
304
|
605
|
22.7
|
Nov-2017
|
|
Hateruma Isl.(2)
|
2,825
|
0
|
3
|
52
|
463
|
1278
|
841
|
188
|
266
|
720
|
28.2
|
Aug-2014 Aug-2015
|
(1) Only Fukugi trees with DBH larger than 25 cm were measured.
(2) Fukugi trees with DBH larger than 5 cm were measured.
|
This may have resulted from the dramatic landscape transformation into grassland for cattle grazing, and into other areas that are not being actively used by the local people.
Ethnobotanical uses
The traditional uses of Fukugi trees were coded into 11 categories, and the importance of Fukugi trees in people’s lives is summarized in Table 2. All respondents commented on the use of Fukugi tree as a windbreak. Approximately one-fourth of the respondents indicated that Fukugi trees provide diverse functions, such as amenity landscape, timber, ritual ceremony, and cooling air inside the homestead (Table 2).
In terms of respondents’ age, among the 20 respondents, we were able to access only one respondent in the age of 30 s, two respondents were in their 50’s, while the other 17 respondents were over 60 years old (see Appendix). Further, the younger respondent in his 30 s did not state any uses of Fukugi trees, other than as windbreaks.
Fukugi trees in Okinawa were primarily used for homestead and farmland windbreaks. Okinawa has a subtropical monsoonal climate, which suffers from frequent strong typhoons in the early summer to late autumn and winter wind from the north. Windbreaks are essential to crop planting and to people’s houses. In the past, traditional houses were made from timber and thatched roofs, which was the reason why homestead windbreaks were prevalent on the islands. Nowadays, the transformation of house building in concrete contributes to the cutting of many windbreaks in Okinawa. However, many people still cherish their traditional windbreaks.
Table 2
Traditional uses pertinent to their relative citation frequencies (RFC)
Coding
|
RFC (%)
|
Homestead windbreak
|
100
|
Homestead firebreak
|
10
|
Tree belts prevention from tidal water
|
5
|
Landscape amenity
|
25
|
Timber
|
20
|
Dyeing
|
15
|
Windbreak for the home garden
|
10
|
Cooling the air inside the homestead
|
15
|
Praying for the gods
|
15
|
House borderline
|
5
|
Eating fruits
|
5
|
One interviewee, K. (male, 68 years old, Bise hamlet), described the indispensable role of Fukugi trees as house windbreaks. He declared that “without Fukugi trees, we would not be able to live in Bise (hamlet). The Fukugi tree is green all year round. The north wind is very strong.” Fukugi windbreaks are also believed to be superior to concrete walls, although the Fukugi hedgerows have been removed and replaced by concrete walls on many islands. Another interviewee, M. (male, 50 s, Aguni Island) told us in detail that in Aguni Island, Fukugi tree lines standing together with porous coral stone fence can absorb (mitigate/weaken) the damaging power of strong winds. He recalled the case of a neighborhood grandmother, who changed to using a concrete wall as windbreak and found that the winds became stronger before hitting the house.
Old growth trees were important timber sources in remote islands, especially during the period immediately after WWII when resources and materials were depleted due to the war. S. (male, 60 years old, Hateruma Island) said that approximately 80% of the timber was from the neighboring Iriomote Island. Old windbreaks in most of the survey sites were selectively harvested and the trunks were submerged in sea water to develop insect repellent properties when used as flooring and poles.
In addition to being used as windbreaks, Fukugi trees contribute to agricultural production in two ways: as green manure for crops and as soil improvement materials used to fill in land. In remote small islands, there are very few natural forests that farmers can use for their farmland. Fukugi leaves can be buried in farm soil to decompose into humus or burned to improve soil fertility.
Interviewees also described Fukugi leaves as being used as toys and as trees providing shade for breaks during hot summers. M. (66, male, Bise hamlet) said that “In summer, it is cool under the trees as it provides shade from strong sunshine. We ate lunch under the trees and take a nap, then went to farm work at 4:00 pm.” Many senior residents from islands north of Okinawa Island vividly recalled memories of their childhood when children often used to cut one leaf from a pair of leaves to make leaf sandals to play with their friends around the village.
In the southern islands of Okinawa Prefecture, many informants over 60 years old stated that they ate the fruits during their childhood. Fruits ripen in August and are similar to oranges with four or five seeds. Very few fruits are presently eaten, and many residents do not know that the fruits are edible, after the import of fruits from overseas and mainland Japan in recent decades.
Fukugi trees are important dye-producing plants in the Ryukyu Islands. Historically, Fukugi trees have been widely used to extract yellow dyes for textiles, especially for costume fabrics used in traditional festivals and everyday life. Recently, hands-on workshops have been held for groups of older people and local children (Figs. 4 and 5). Such workshops can potentially be held for tourists, since about 10 million tourists currently visit Okinawa each year.
Sacred Trees
Fukugi trees also contribute to a local community’s spiritual life as sacred forests, either as pure Fukugi forests or mixed in forests with other native tree species. For most sacred sites, one or a small number of big Fukugi trees still exist; however, groves of big Fukugi trees were found in the sacred sites utaki and ashagi (Table 3). In Okinawa, a hamlet is based on a territorial band, as well as a kinship and community. Each hamlet has its own sacred places of utaki, ashagi, or haisho. Utaki are usually located on the outskirts of hamlets and are places for the veneration of guardian gods and ancestors. Ashagi or haisho are always located inside hamlets, usually at the center, where guardian gods were summoned to hold ceremonies and rituals, with the harvest festival being the most common. Within approximately 37 hamlets, utakis and/or other sacred sites had large remnant Fukugi trees. The oldest tree found in the sacred sites was in the utaki of the hamlet of Furugen, Yomitan Village, and is estimated to be 344 years old. The ashagi in Nakaoshi contained the oldest Fukugi trees. A large Fukugi tree that is 12 m tall and 360 years old, is at the southern entrance to the Kannonji (the Goddess of Mercy) Temple, Kim Town, in the middle part of Okinawa Island. The other three sacred sites are located inside the hamlets surrounded by Fukugi trees.
Old Fukugi trees/forests found in sacred sites can be categorized into two types. One type contains only planted Fukugi trees, such as the Tōbaru utaki and ashagi (Fig. 6), the Nakadomari ashagi of Kunigami Gun, and in Furugen the utaki of Nakagami Gun (Table 3). The second type is a mixture with other native tree species such as Bischofia javanica and Ficus microcarpa, and includes Hiji ashagi (Fig. 7) and Kannonji (the Goddess of Mercy) Temple, Kim Town. Hiji ashagi is located inside the Kodamamori forest, east of the hamlet. Approximately 20 large Fukugi trees were found dispersed within the natural forest and have been well preserved since the origin of the hamlet. The average DBH of Fukugi trees in these four sites was estimated to be over 40 cm. Fukugi trees were the tallest in the Hiji ashagi since they were growing inside a thick natural forest. The other three sacred sites were located inside the hamlet surrounded by Fukugi trees. We observed that all Fukugi trees were growing in a circle. Thus, we assumed that the Fukugi trees were planted to enhance the sacred environment as internal circles in the natural forests.
Table 3
The biggest Fukugi trees found in the sacred sites of utaki, ashagi
Utaki/Ashagi
|
Tree number
|
DBH (cm)
|
Estimated tree age (yrs)
|
Tree height (cm)
|
Maximum
|
Average
|
Maximum
|
Average
|
Maximum
|
Average
|
Tōbaru
|
21
|
76.6
|
47.4
|
282
|
189
|
1172
|
897
|
Hiji
|
20
|
66.1
|
42
|
264
|
168
|
-
|
1480
|
Nakadomari
|
20
|
62.5
|
42.1
|
250
|
168
|
1550
|
1450
|
Furugen
|
12
|
86
|
49.5
|
344
|
198
|
1306
|
1048
|
Tōbaru utaki and ashagi were built in the same place inside the hamlet with surrounding Fukugi trees. |
Hiji ashagi is a thatched roofed small building covered by a thick forest, located on the top of the hill behind the hamlets. In addition to planted Fukugi trees, large Bischofia javanica trees were also present.
Nakadomari ashagi is located in the middle of the village, and is now used as a public playground and for annual sacred ceremony.
Furugen utaki is located inside the village covered by a grove of a pure Fukugi forest.
Heritage Trees
In Japan, well-known large trees and old-growth trees were selected and archived from the perspective of “ancient trees living together with the local residents.” A heritage tree is typically large and old, with unique values that are closely interwoven with local life. The major criteria for heritage tree designations are age, rarity, and size as well as aesthetic, botanical, ecological, and historical values of the trees [21]. In Okinawa, large trees/old growth trees with high academic value, or cultural value derived from history and tradition, are designated as heritage trees at the municipal level.
Thirteen sites of Fukugi trees/forests have been designated as heritage trees in Okinawa (Table 4) [22]. These heritage trees include large trees in historic sites (1), sacred places (6), and remnant homestead windbreaks (6). The largest Fukugi tree is located in the Uchima udun (Fig. 8) and was estimated to be 364 years old (surveyed on March 12, 2009). Udun is the ruin of a mansion inhabited by a relative of the Ryukyu King, a prince, or an Aji (a title and rank of nobility immediately below a prince). Uchima udun was designated as a national cultural property in 2011. It is believed that the Fukugi trees were planted in 1736, when the main building was changed from a bamboo windbreak to a Fukugi tree. Currently, 49 large trees remain at the site [23].
Table 4
Fukugi trees/forests designated as heritage trees in Okinawa Prefecture
Designated Year
|
Place
|
Municipality
|
Properties
|
Dimensions of the biggest Fukugi tree
|
Survey date
|
Diameter at breast height (cm)
|
Tree height (m)
|
2003
|
Uchima Udun
|
Nishihara Town
|
sacred site
|
81
|
14.1
|
Mar. 12, 2009
|
2004
|
Kannon Temple
|
Kim Town
|
sacred site
|
90.5
|
12
|
Dec. 27, 2009
|
2004
|
Tonaki Bansho (village public office) ruins
|
Tonaki Village
|
historic site
|
60.3
|
14
|
Jul. 2010
|
2005
|
Kijoka
|
Oogimi Village
|
remnant homestead windbreak
|
41.4
|
6
|
Nov.2009
|
2005
|
Furugen Ugan
|
Yomitan Village
|
scared site
|
87
|
13.6
|
Nov. 2009
|
2005
|
Nagahama Village
|
Yomitan Village
|
remnant homestead windbreak
|
64.5
|
9.5
|
Nov. 2009
|
2005
|
Gushikami
|
Yaese Town
|
remnant homestead windbreak
|
76.5
|
8.6
|
Nov. 2009
|
2006
|
Bise
|
Motobu Town
|
remnant homestead windbreak
|
72.6
|
|
Aug. 2008
|
2006
|
Ungusuku Utaki
|
Tamara Village
|
sacred site
|
68
|
9.3
|
Mar., 2010
|
2007
|
Uineetsuzu
|
Tamara Village
|
sacred site
|
70
|
12
|
2007
|
2007
|
Minna utaki
|
Tamara Village
|
sacred site
|
58.9
|
8.2
|
Mar., 2012
|
2012
|
Ige
|
Uruma City
|
remnant homestead windbreak
|
69.4
|
12
|
2012
|
2013
|
Agarie
|
Ie Village
|
remnant homestead windbreak
|
76.2
|
11.9
|
Dec. 12,2009
|
Symbol Trees
The cultural and aesthetic values of this species have been highly appreciated, resulting in the species being selected as a city tree, town tree, or village tree in eight municipalities. Among the 41 municipalities (cities/towns/villages) in Okinawa Prefecture, eight municipalities have designated Fukugi trees as their symbol trees (Table 5) [24, 25]. Japan has three levels of governments: national, prefectural, and municipal. There are four types of local government municipalities in Japan that are based on population size: cities, towns, villages, and special wards (the ku of Tokyo). In terms of other symbol trees in Okinawa, the Ryukyu kokutan (Diospyros ferrea) municipality ranks among the top 10, followed by the banyan tree (Ficus microcarpa), which was designated within five municipalities. However, no municipality has officially recognized a Fukugi tree as a symbol tree outside Okinawa Prefecture in Japan.
Table 5
List of counties with Fukugi tree as the city/town/village tree in Okinawa Prefecture
County
|
City
|
Population*
|
Naha City
|
317951
|
Kunigami Gun
|
Motobu Town
|
13113
|
Onna Village
|
10789
|
Nakagami Gun
|
Yomitan Village
|
39615
|
Shimajiri Gun
|
Aguni Village
|
715
|
Tonaki Village
|
393
|
Kumejima Town
|
7271
|
Miyako Gun
|
Tarama Village
|
1111
|
Data source: http://www.midorihana-okinawa.jp/?page_id=90 |
* Population on March 1st; data source: Okinawa Prefectural Office (25) Data source: http://www.midorihana-okinawa.jp/?page_id=90 |
Tonaki, which is a small village on an isolated island in Okinawa, with a population of 355, an area of 3.75 km2, and a periphery of 12.5 km [26], was designated as a Fukugi tree village in 1992. The village homepage states that almost all houses have Fukugi trees as windbreaks (Fig. 2), with the trees being used to build and protect houses from salty sea water, strong winds, and fires (Fig. 3). Moreover, it is believed that Fukugi trees can bring happiness and prosperity and exist in harmony with the Okinawa subtropical landscape.
Island people highly value Fukugi trees as windbreaks and for ameliorating the microclimate. People in the smaller islands value trees more than people in mainland Okinawa [27]. Some residents even believe that cutting Fukugi trees will cast a curse and bring misfortune to a family [28]. A 50-year-old woman mentioned that she dared not break even a single branch of her neighbor’s Fukugi trees, which the old lady believed had a spirit dwelling in it.