Gandong Cai and Mingjie Cai
2019 - Present
蔡淦东&蔡明洁
2019至今
1 The Ignored Urban Mental Desire
The development of diverse disciplines resonates with the growing and evolving of human desires throughout history. The spatial design professions echo with such desire by organizing the built environment and managing the spatial systems. Environmental issues acquire more attention in the era of the Anthropocene along with the ongoing process of urbanization, emphasizing the importance of urban public health as the collective desire of all humans.
The Landscape Architecture profession is established on the understanding of the relationship between the improvement of the urban environment by human effort and public health. Currently, the standard for evaluating livability of a city relies largely on aspects such as the quality of public space, greening rate, and accessibility to parks. It is well discussed that landscape can accommodate emotion and relief pressure thus has a positive meaning to people's mental health: healing garden and therapeutic landscape as specific types of landscape can help to improve physical and mental health; contextual therapy theory in psychology also acknowledges the function of a picturesque environment in mental relaxation [1].
However, attention is largely paid to the physical aspect of public health. Kevin Thwaites points out that although the importance of enhancing human life quality through the design of urban space is well understood, it seems implicit that their capacity to help people mitigate the effects of mental fatigue may be assumed to accrue automatically as a by-product of other more general urban design principles [2]. This is demonstrated in two aspects: 1) the study of public mental health in planning and green space system scale is inadequate, and specific type of landscape like healing garden is incapable to tackle with systematic problems; 2) different groups of user have variegated mental desires in public space which cannot be addressed simply by a generic solution offered by the common urban open space (urban park). The landscape related to mental health is still functioning as a therapy within conventional medicine protocols and does not yet seem to have extended far into consideration of design in the wider public realm [3]. Thus, this essay introduces the conceptual project "Tokyo Loneliness Tree Hole Plan" which starts from the urban public space system and selects a specific group of users to analyze their mental desire in the urban environment, in order to explore the new possibility of advocating urban mental health through spatial design, and conceive the urban spiritual infrastructure which is a new systematic framework after the grey infrastructure and green infrastructure.
2 Design for Whom and the Recognition of Loneliness
It's a consensus to design public space for the public. Seeing the public as the majority of people, however, results in the neglect of the minority and their desires. The design of public space focuses on the typical majority: those who can freely behave in public space and enjoy the encounter and interaction with strangers. There is another group of people who are reluctant to bother others and unwilling to be disturbed--feeling nervous in crowded places--which are the "lonely" individuals that should not be ignored in the design of public space.
"Loneliness" has long been delineated as a negative emotion or mental condition and has been placed on the opposite side of "positive communication" and sharing, under the western binary context. Medical Sociologist Aaron Antonovsky establishes the theory of "Salutogenesis" [4], promoting the shift of modern medical science from the pathogenic orientation model which excessively focuses on the negative impact of potential illness and lowering sick risk, to the salutogenic orientation model that faces one's physical and mental health condition positively. At the society level, the pathogenic orientation model emphasizes the hazard of illness to alarm the people, while at the individual level it leads to the attention being solely focused on the disease once it is identified: either way lacks a synthetic understanding of the human complexity in health [5]. This resonates with the situation of the lonely individuals in the city who are suffering from the pressure of being lonely, while society is indicating the danger of loneliness and the necessity of eliminating loneliness ①. Scholars from the landscape architecture profession have applied the salutogenic orientation model and pointed out that urban landscape has the potential to relieve mental stress and generate a positive understanding of the mental condition by offering a pleasurable experience [6]. We believe the urban environment should follow the Salutogenesis theory and create a new understanding of loneliness, by encouraging the public to get along with loneliness through spatial design methods.
3 Site Selection and Research Methods
"Tokyo Loneliness Tree Hole Plan" is the first-prize-winner proposal of the Eliminate Loneliness Idea Competition. The proposal targets the loneliness issue in Tokyo as a response to the topic of Design for whom. The behavioral mode of self-restraining and keeping social distance in Japanese public life, together with the extremely high living pressure and demographic density, lead to the prevalence of loneliness in every corner of the city--the lonely individuals are the minority users in public space and the majority in Tokyo at the same time. Furthermore, "loneliness" as an oriental aesthetic concept emphasizing the status of getting along with oneself, has been reflected in lots of art and literature pieces ②, which justifies and unifies the selections of both the topic and the site: to establish a new cognitive mode of loneliness based on the Salutogenesis theory in a city dominated by the phenomenon and aesthetics of loneliness by the method of spatial design. For this purpose, the proposal starts from the study of mental desire and aims at providing suitable space for getting along with loneliness, through mitigating the negative impact of the mental status.
4 Urban Tree Hole: The Empathy about Loneliness between Human and Nature
The lonely individuals concern less about the feeling of loneliness per se than the way loneliness is treated by society and the impact on others by being lonely. As an antidote to loneliness and a strategy for depathologizing it, privacy may be as effective as company for these people [7]. They might prefer to talk to a “tree hole”: a space that can be easily found around, will not respond and disturb others, but provides enclosed shelter and the feeling of safety. Anyone who wants to spend some time alone can go into such space without worrying about the outside world.
Thwaites points out that a restorative urban open space structure is emerging [8]: moves away from the idea of large discrete open areas to more of a web or mesh-like structure that links together a system of smaller spaces, whose quantity and high accessibility in cities have the advantage in tackling mental issues in a timely manner. The "Tokyo Loneliness Tree Hole Plan" proposes such a spiritual infrastructure network of small "urban tree holes" as a systematic maneuver to provide the lonely individuals in Tokyo a chance to get alone with themselves, with the space, and with loneliness.
Shibuya, the center of Tokyo, is selected as the site for implementing the plan. On one hand, as the major commercial center and the most stressful area to live and work, Shibuya perfectly represents the Tokyo loneliness; on the other hand, given that only 6 percent of Tokyo's urban area is classified as open space [9], Shibuya with the highest building density in the city is desperate for the "urban tree holes" to be inserted. The project proposes operative tree hole prototypes according to specific site conditions and conceives three different spatial modes to create innovative public space in Shibuya by utilizing street retail spaces, sky corridors, and underground spaces.
Instead of creating an isolated place for people to stay in, the tree hole space invites accompanies from nature such as tree, sky, and water to the users, by a sequence of spatial design strategies. Roger Ulrich proves the function of natural element in elevating people's mental health by the observation of a group of patients who experience considerable anxiety [10]: the patients with the tree view had better performance in overcoming frustration, fewer negative evaluative comments, and shorter post operative hospital stays, compared to the wall-view patients. As the most common natural elements, tree, sky and water are ignored in the high density and fast-paced urban life--they are silent and lonely in the city. Through the enhancement of the loneliness aesthetics between nature and people, the project attempts to establish the oriental concept of empathy: human and nature can "share" and "communicate" the feeling of loneliness temporarily.
4.1 Urban Tree Hole_01: Renovate Street Retail Space
The retail spaces along the street interface with fast iteration speed have great potential to be transformed and embedded the small-scale public space in Shibuya, where the density of commercial and cultural activities is extremely high. The design strategy of Urban Tree Hole_01 focuses on the way of seeing by switching the interior and exterior spaces. The tree hole spaces are hidden in the urban context by the design method of embedment in renovated stores along the retail street, which reduces the impact of the original urban interface. From the exterior, a two-side mirror as the new façade of the renovated space reflects the image of the user and the background city; from the interior, the mirror separates the city and the user who is pulled away from the context and obtains a moment to rediscover the overlooked landscape in the city she originally familiar with. The technique of borrowing scenery is used to involve in the tree hole the street tree which becomes a companion and listener of the tree hole user. As the new city spiritual infrastructure, the embedded tree hole spaces that distribute in the city but hide in the street context provides the citizen a moment of meditation with a Zen-garden-like experience.
4.2 Urban Tree Hole_02: Utilize Sky Corridor
While the vertical transportation mode depending on the elevators represents an important movement in high-density cities, the sky corridors between buildings become one kind of horizontal connected open space for promoting the openness and publicity of the overhead space. Though the sky is originally a part of the cityscape, congested high-rise buildings in the city make people gradually lost the instinct to look up at the sky--climb up to the skyscraper and overlook the cityscape becomes the normal viewing mode. Through the strategy of obstructive scenery and sight manipulation, the Urban Tree Hole_02 utilizes sky corridor between buildings to create space for users to briefly stay alone. Compare to the common sky corridor that emphasizes transparency, the tree hole's external scenery is deliberately blocked by sidewalls. Only the sky is reflected by tilted mirrors on both sides of the corridor, which forces the user to focus on the mirrors by his feet. Consequently, a spiritual infrastructure is established through the sky corridor tree holes built between buildings in the city, and the user can look down to meet the sky which should have been found by looking up. Thus, people and the forgotten sky achieve an empathetic moment on both the physical and mental levels.
4.3 Urban Tree Hole_03: Excavate Underground Space
The street interface and high-rise buildings occupy the visible ground and overhead space in the city. The underground, however, is an invisible potential space in the city. By locating the Urban Tree Hole_03 as the small-scale public space below the busiest intersection in Shibuya, the tree hole space provides a quiet place in the busy city. Except for the underground part, the design of the tree hole_03 also includes a rain garden above ground. Since no one will care about where the falling rain is going to in the center of a highly-dense metropolitan city, our strategy for the tree hole intend to collect and filler the city runoff water, and to transform them from invisible raindrops into a visible water feature in underground space. The water curtain can effectively block the ground noise at the same time, which helps to create a place for users to get along and communicate with the nature element—water. From above ground to underground, from never being noticed to being the focus, our strategy—scenery replacement—turns the originally invisible city underground and raindrops into the visible empathetic objects for the lonely users.
4.4 Use and Management of Urban Tree Hole
Besides the spatial design strategies, the “Tokyo Loneliness Tree Hole Plan” considers two questions simultaneously: how to convey the enjoyable experience of getting along with loneliness, and establish a “comprehensive share structure” among citizens through using this new type of public space? Therefore, the <Tokyo Loneliness Tree Hole Guide> is introduced in the project. This guidebook not only shows the locations and instructions of the urban tree holes but also provides a message board for the users to write down and share their lonely story and the experience in the tree holes. In this way, users are circulating and sharing the <Tree Hole Guide>, transforming it into a collective communication tool for each lonely individual.
Also, to balance the publicity and privacy, security and management issues, each tree hole’s design is based on the scale for one person use, and intend to be operated by a reservation mechanism, through which only one user can enter and use the space at a specific time--a “One Person, One-Time” place is created. The “One Person, One-Time” operation mode ensures that the users can enjoy the space exclusively for a specific time, and the effective reservation mechanism allows the public to take turns to use the space orderly. These urban tree holes propose a new possibility for public life which cannot directly apply the use and management model of the traditional urban public space, given that the two are significantly different. Therefore, the reservation mechanism of “One Person, One-Time” combines with the <Tree Hole Guide>, can support the operation mode of this new type of future public space, which becomes the new infrastructure network in the city.
5 One Person Park: The Possibility of Future Public Space
While the modern city has a clear definition of what is public-owned and private-owned space through the land use and ownership division, there is ambiguity between public and private when it comes to practical issues. Currently, the discussion regarding the vagueness of public and private mainly focuses on the space that is "privately owned but opens its external areas to the public in order to provide more urban open space" [11]. "Tokyo Loneliness Tree Hole Plan" is something different: it proposes space that is public, but offers people a temporary and private place for solitary use through a "one person, one-time" mode. The concept of "private-public space" aims at criticizing the indifference against the diversity of the users' mental desire in the current public space, breaking the banal boundary between public and private, and exploring the possibility of future public space with vagueness--the "One Person Park".
"One Person Park" as a concept has not been discussed before it is mentioned in this essay. Its major differences against traditional urban green space are: 1) while the traditional park is merely public, the "One Person Park" can shift mode between public and private through management; 2) compare to traditional park that occupies a great amount of urban land, "One Person Park" is inserted into the existing urban systems; 3) traditional park owns abundant resource of landscape, while "One Person Park" absorbs adjacent natural elements as the supplement of landscape resource. It is the vagueness in both the ownership status and the spatial image of "One Person Park" that makes it a void yet a promised space of expectation in the public space system [12]. Far from the retrogression of publicity and going back to the private garden or private owned space, "One Person Park" suggests a new communication mode on public sharing.
While "One Person Park" has not been fully discussed yet, the exploration of private use in public space has started. A temporary public art event--Concert For One--was brought to Boston, the US in 2019, which provided a chance for one instrument player and one audience to stay in a solitary space for one minute, thus successfully created a private music experience for public space user ③. This art project echoes with the "One Person Park" in the challenges they point out to the current public space function: in an era when interacting programs such as music plaza and amphitheater are everywhere and becomes the stereotype in public space design, can we imagine a new form of public landscape that allows the user to enjoy being alone?
"One Person Park" as an alternative possibility for future public space development should earn more attention in the discussion of urban space design. The COVID-19 pandemic urges us to consider the issue of public isolation and non-contact communication, as well as the new way to use the current public space. There is a huge conflict regarding behavioral mode between the openness and interaction in public space and the hygiene protocols of avoiding physical touch during the pandemic. To what degree can current public space design reflects and addresses the physical and mental desire of the city dwellers? How can the concept of "One Person Park" enrich and complement the study of urban public life?
6 Conclusions
This essay investigates the mental desire in public space through the introduction of a conceptual design project, proposes a set of spatial strategies for eliminating the public's prejudice against loneliness, and offering suitable public space for the lonely individuals living in cities through the study of different scenarios. As a competition entry, "Tokyo Loneliness Tree Hole Plan" brings up three operational prototypes as well as intervention modes instead of construction guidance for any designated site with specific technologies. Thus, the project concerns less the management issues when the tree holes are implemented in reality, than the discussion of its value in exploring mental-oriented design intervention in urban space development. Furthermore, given that urban loneliness is not the only mental health issue in our cities, the strategy applied should be various regarding different mental desires. The thoughts and ideas that emerge in "Tokyo Loneliness Tree Hole Plan", however, have the reference value for public space planning and design in the future.
In the period of post-pandemic, with people's tendency to stay alone or restrict getting together in public space, how design can fulfill the new desire--especially the mental desire--becomes the new agenda for designers. Mental health awareness needs to be integrated into all elements of health and social policy, health-system planning, and health-care delivery [13], including the design and construction of urban public space and infrastructure. More ideas based on specific background, city, and public desire should be taken into consideration in the future, in order to promote new discussion and practice in a broader territory and context.
1 被忽视的城市精神需求
纵观人类历史，不同学科的创立与发展都体现了人类需求的不断变化与迭代。相较于其他领域，空间营建学科对人类需求的回应体现在对建成环境的空间梳理与系统组织之上。随着人类世的到来与城市化进程的加深，环境问题日益得到重视，保障城市中的公共健康成为人类的集体需求。
景观设计学建立在人类对城市环境提升与公共健康的关系的理解上。今天，高品质的公共空间、丰富的活动项目、高绿地覆盖率与可达性等指标已成为评价一座城市是否宜居的重要参考。景观对人的精神健康确有积极意义：城市景观具有调节心情与缓解压力等针对精神健康的功能，以康复花园与医疗景观为例的特定类型景观已被证明对人的身心健康均有积极作用；心理学上的情景治疗理论认为，风景优美的疗养环境对心理有放松镇静等作用[1]。
然而，当前城市建设中对公共健康的关注更多集中在物理层面。凯文•思韦茨认为，城市空间设计对生活质量提高的意义已被充分肯定，但其对于精神层面的作用，更多地被当作城市设计策略的“副产品”，没有得到足够的讨论[2]，主要体现在两个方面：1）目前城市公共空间的规划与设计缺乏从绿地系统等宏观尺度上关注公共精神健康问题，疗养花园等特定类型的景观无法有效应对系统性的问题；2）公共空间中使用者的精神需求根据群体的不同而具有多样性，但一般城市绿地（如公园）所具有的精神健康调节功能过于宽泛，无法有效回应人们的具体诉求。鉴于关注精神健康的景观尚未从属于医疗系统的花园拓展至更广阔的城市公共领域[3]，本文以“东京孤独树洞计划”概念方案为例，提出一种从城市公共空间系统入手，透过特定受众群体的选取以及对他们在城市中精神需求的分析，探索空间设计促进城市精神健康的新可能，并设想一种继灰色基础设施和绿色基础设施之后，系统性的城市“精神基础设施”的新景观形式。
2 为谁设计与认知孤独
公共空间的服务对象为公众是设计师的共识。然而，把“大众”当成全部个体的合集，造成了对“小众”使用者需求的忽略。公共空间的设计多以典型的大众使用者为对象：他们能自在地在开放场所中进行各种形式的活动，且享受在公共空间中与陌生人的相遇和互动。但城市中也存在着另一类群体，他们不希望被打扰，也避免打扰他人，在人流密集的场所会倍感紧张——他们是公共空间中“孤独”的个体，也是公共空间设计中不应被忽略的使用者。
“孤独”一词在西方二元论语境下长期被渲染成一种与“积极交流”“分享”相对立的消极精神或情绪状态。医学社会学家阿兰•安东诺夫斯基提出“健康本源论”（Salutogenesis）概念[4]，认为现代医学应从过度关注潜在疾病可能对身体产生的负面影响、主张规避风险的疾病本源导向，转为健康本源导向（Salutogenic Orientation）的认知模式，即直视自我的身心健康状态。疾病本源导向在社会层面上表现为强调疾病危害性以起到社会警惕作用，在个人层面上则表现为注意力被过度集中在疾病本身：两者都缺乏对健康复杂性的综合认知[5]。这与城市中的孤独群体面临的状况相似，即社会强调孤独的危害而强调消除孤独①，个体也因自身的孤独产生心理负担。关于健康本源导向模式在空间营建学科上的应用，已有景观学者指出，城市中的景观空间能营造令人愉悦的氛围，减缓压力，有利于产生积极的心理认知 [6] 。笔者认为，社会环境应以健康本源导向的理论为支撑，通过空间营建的手法更新人们对孤独的认知，鼓励大众学习与孤独相处。
3 项目选址与研究方法
“东京孤独树洞计划”是2019年“消除孤独概念竞赛”（Eliminate Loneliness Idea Competition）的一等奖作品。方案选择以“东京孤独”作为城市精神需求的研究对象，一方面是对“为谁设计”议题的回应。日本公众在公共生活中自我克制与注意保持社交距离的特质，加之东京地区极高的生活压力与人口密度，导致了孤独感渗透在城市的每个角落——在东京，孤独者既是公共空间使用群体里的小众，又是这座城市无处不在的大众。此外，“孤独”在东方思维中作为一种强调与自我相处的美学，在艺术与文学作品中反复出现②，使得本方案的选题与选址理由更为充分与统一：在一座具有孤独现象与孤独美学的城市，利用空间设计的手法，建立基于健康本源论的孤独认知模式。为此，方案从精神需求层面入手，通过疏导孤独感带来的负面影响，旨在为孤独者提供适宜的享受孤独的空间。
项目首先以健康本源论为研究的理论基础，重新思考并提出对孤独的积极理解，并以“情景为基”（scenario-based）的调研方法，通过观察、记录、图像转译等手段，描绘出东京各类人群在不同日常情境下展现出的孤独感；项目进而分别在城市尺度构筑“精神基础设施”以为东京大众的“精神需求”提供系统性的策略，在空间尺度创造出一系列以健康本源导向的、能引起东方式共情的新型公共空间。
4 都市树洞：人与自然关于孤独的共情
在东京，最困扰孤独者的并非孤独本身，而是社会看待孤独的方式，以及担心自己的孤独影响他人而造成的心理压力。对于这类人群而言，一个独处空间的情绪慰藉作用并不亚于得到朋友的陪伴[7]。因此，他们在面对孤独时更倾向于寻找一种类似“树洞”的交流对象：一种在身边容易找寻到的、不会直接答复或回应也不对他人形成困扰的、可以提供虚空且具有安全感的遮蔽空间。在这样的空间中，任何人都可以毫无压力地与自我独处片刻，也不必担忧外部的眼光。
思韦茨认为一种新的恢复性城市公共空间结构正在形成[8]：它们跳脱出传统的大型城市公共空间思维模式，迈向一种由小型空间组成的网状结构；它们可观的数量和高可达性在及时应对精神健康问题上更具优势。“东京孤独树洞计划”提出的正是在东京创造一系列的“都市树洞”，作为一种系统性的对策为城市构建出一层由小型嵌入式空间构成的新型精神基础设施网络，为东京孤独者提供一个与自我、与空间、与孤独共处的机会。
项目选择位于东京市中心的涉谷区作为树洞计划的实施场地。一方面，涉谷作为东京生活工作压力最大的城区之一，最能体现东京市民的孤独感；另一方面，东京公共开放空间面积占比仅为6%[9]，其中建筑密度最大的涉谷区对植入“都市树洞”有着迫切需求。项目依据不同的具体场地条件，创造不同的、具有可操作性的树洞空间营造范式，通过激活临街闲置商铺、搭建或利用高层间连廊和开发地下空间三种树洞空间模式，为土地资源稀缺的涉谷区创造新的嵌入式公共空间。
树洞空间的营造并非令人置身于封闭的环境中，相反，项目利用借景、障景与换景的空间设计手法，为使用者提供了来自自然的“陪伴者”：树、天和水。罗杰•尤里奇曾通过一组针对术后焦虑病人的对照试验，论证了与自然元素为伴有利于人的精神健康[10]：能透过窗户看到树木的病人在克服沮丧、保持积极情绪、缩短住院时间等方面的表现均优于病房窗外是一面砖墙的病人。树、天、水作为最常见的自然元素，在高密度、快节奏的城市生活中同样常常被忽略——它们也是城市中的另一种无声的孤独者。通过强调与自然共处与对话的孤独美学，项目试图构建自然景观与人之间的东方式共情：人和自然将短暂地“分享”与“交流”彼此的孤独感。
4.1 树洞一：改造临街商铺
在商业文化活动密度极高的涉谷进行公共空间的置入，迭代速度快的沿街界面具有很大的改造与利用潜力。树洞一的设计策略着重于通过内外空间的切换改变观看的方式，利用嵌入空间的手法改造临街商铺，使树洞空间消隐在街道之中，降低对原城市界面造成的影响。被改造后的立面换上落地式单向透视玻璃旋转门，从外部观看镜面，得到的是自我与城市融为一体的影像；从内往外看，自我与城市通过玻璃分隔，观看者瞬时抽离当下的同时，也重新发现了城市中被忽略的景观。运用借景手法，行道树被纳入树洞空间，成为了孤独遭遇的交流者和情绪抒发的倾听者。散布于城市又消隐于街道中的临街树洞空间作为新植入的城市精神基础设施，让原本步履匆匆的城市居民获得片刻犹如日本禅宗园林中的静观与冥想的体验。
4.2 树洞二：空中连廊
当以电梯为主体的纵向式交通成为高密度城市人群的重要活动轨迹时，楼群间的空中连廊作为水平向的连接空间，提升了城市空中的开放性与公共性。天空本是景观中的一部分，城市中密集的高楼大厦渐渐让人丧失了仰望天空的原始本能，登上摩天大楼居高临下地俯瞰城市景致成为都市人习惯的观看模式。树洞二着眼于林立的高楼之间，通过障景和视线操纵手法，增设或利用空中连廊，创造供使用者短暂停留的树洞。一般的空中连廊强调视线的通透，而树洞二的空间设计则刻意通过墙体遮挡外部景色，仅于两侧的副廊以倾斜镜面将天空反射进来，使得使用者视线聚焦于脚下的镜面。通过一处处架于高楼之间的场所构成的精神基础设施，惯于向下“俯瞰”的都市人在连廊中低头发现本需向上“仰望”的天空，人与被遗忘的天空在城市中在物理和心理层面实现孤独共情。
4.3 树洞三：开发地下空间
沿街界面与林立高楼分别占据了城市可视的地面层与高空，而地下则是城市中不可视的潜力空间。树洞三着眼于涉谷最为繁忙的十字路口下方，通过置入地下公共空间，在闹市中创造出静谧的场所。除地下空间外，树洞三的设计还包括地面上的雨水花园。在高度密集的大都市中心，落下的雨水去往何处从无人关心，此处的树洞空间设计通过收集和过滤城市地表雨水，将不可见的雨滴汇集置换成可见的地下水帘。同时，水帘能有效隔绝地面噪音，有助于塑造城市中无声的孤独者与自然之水的独处交流场所。从地上到地下，从不被察觉到成为视觉焦点，原本不可视的地下空间与城市雨水，透过换景的手法，变成了城市孤独者在地面之下可视的共情对象。
4.4 都市树洞的使用与管理
除空间设计策略外，“东京孤独树洞计划”还同时思考：如何通过这一新型公共空间的使用，将享受与孤独共处的心境进行传递，并形成另一层情感共享机制？为此，项目引入了《树洞指南》手册。手册不仅记录了树洞分布的位置与使用方法，同时拥有使用后的留言功能。作为共享资源与媒介，《树洞指南》可供使用者传递和借阅，记录下自己的故事和心境，成为孤独者集体交流的工具。
另外，为了兼顾空间的公共性与私人性，以及安全与管理问题，项目在空间设计上基于一人使用的尺度，采用分时预约使用制，即同一时段只允许一位使用者进入，营造“一人一时”的场所。 “一人一时”保证了使用者能在特定时间内独享空间，而一套有效的预约机制则使得公众能有序地轮流使用。这种都市树洞为公共生活提出了一种新的可能，但因为其特征与传统的城市公共空间有较大差异，无法直接沿用后者的使用与管理模式。“一人一时”的预约制度结合《树洞指南》手册，共同支撑起这种新型未来公共空间的运作模式，使之成为城市中新的基础设施网络。
5 一人公园：未来公共空间的可能性
现代城市空间虽通过用地性质与所属权明确划分了公有与私有的界线，但在具体使用上，公有与私有的界线往往具有模糊性。目前针对公有与私有模糊性的讨论主要集中在“所属权为私有，但向公众开放，以填补城市公共空间不足的缺口”这一类的空间上[11]。本文借由“东京孤独树洞计划”讨论的则是另一种模糊性：虽为公共空间，但“一人一时”的模式为有独处需求的使用者提供了临时的城市私密空间。本项目提出的“私人公共空间”概念，正是在批判现有公共空间忽视使用者心理与精神需求多样性的基础上，打破公共与私人的固有界线，探讨一种未来可能出现的具有模糊性的新公共空间形式——“一人公园”。
“一人公园”的概念在本文之前尚未被提出与讨论。“一人公园”与传统的城市公园绿地具有较大的差异，主要体现在：1）传统公园仅具有公共性，“一人公园”通过管理实现公共性与私密性的切换；2）传统公园占据城市空间，“一人公园”运用嵌入的方式消融于城市已有空间体系中；3）传统公园拥有丰富的景观资源，“一人公园”通过纳入周边的自然元素作为自身景观资源的补充。正因为“一人公园”在公私属性及空间形象上的模糊性，使其具有巨大的潜力，成为已有公共空间体系的有效补充[12]。需要强调的是，“一人公园”并非公共性的倒退，其内核绝非私人庭院或私有化空间，而是基于公有与共享的一种新的交流模式。
“一人公园”概念虽尚未被广泛讨论，但对于公共空间中独处功能的探索已有案例。美国波士顿曾于2019年举行了一场城市临时公共艺术活动——一人音乐会（Concert For One），其在城市公共空间中创造出一名演奏家为一名听众演奏的一分钟音乐会，让使用者拥有一次在公共空间中享受专属一人的音乐体验③。该项目与“一人公园”异曲同工之处在于对现有公共空间的功能发出的挑战：在音乐广场、户外剧场等鼓励集体参与的功能性空间成为公共景观陈词滥调的今日，是否可能出现一种新的景观形式，允许空间使用者享受一人一时的乐趣？
“一人公园”作为未来公共空间的一种发展可能，在今后的城市空间设计讨论中应得到重视。此外，2020年新冠肺炎疫情（COVID-19）所带来的空间隔离和无接触交流，让设计师反思当前公共空间的使用新模式。公共空间过往所强调的开放互动交流与防疫工作提倡的避免物理性接触与空间使用者在行为模式上存在着巨大矛盾。公共空间设计能在多大程度上反映并应对城市居民的身心需求？“一人公园”理念又能在何种意义上丰富与补充关于城市公共生活的研究？
6 设计反思
本文通过一项概念设计实践探讨了公共空间中使用者的精神需求，并以城市中的孤独群体作为研究对象，提出了一套旨在消除大众对孤独的偏见，并为孤独者提供适宜的公共场所的结构性空间改善策略。“东京孤独树洞计划”作为竞赛方案，树洞空间的设计应当被理解成三种操作原型或介入模式，而非明确指向具体选址和建造技术的落地项目。因此，虽然方案对于树洞空间实际投入使用的管理没有详细谈及，但其最大的价值在于探讨以精神健康为导向的设计介入城市空间营造的可能性。其次，城市中的精神健康问题远不止城市孤独，在不同城市应对不同的精神需求所采取的策略也有所差别。但“东京孤独树洞计划”所引发的思考及提供的思路，具有被日后的公共空间规划设计参考的价值。
在后疫情时代，在更多数量的公众倾向独处或对聚集有所顾虑的情形下，如何通过设计满足公众生活的新需求——尤其是精神需求——已成为设计师面临的新议题。精神健康应被纳入到一切与市民健康相关的社会政策、系统规划及医疗保健服务当中[13]，其中涉及城市公共空间与基础设施的设计与营建。日后，更多基于特定时代背景、特定城市与公众需求的思考，将促进在更广的地域和层面上的讨论和实践。
NOTES
① This project is the entry proposal of an international competition under the topic "Eliminate Loneliness". The use of "eliminate" reflects the social tendency of seeing loneliness as a disease and negative issue. The proposal is entitled "from Eliminating to Elevating" with the hope of overturning such negative understanding of loneliness, and suggests a new way of thinking.
② It is commonly acknowledged that loneliness has an important position in Japanese aesthetics and philosophy, which can be found in concepts such as "Wabi-sabi" and " Mono no aware ".
③ This event is launched by the Celebrity Series of Boston and Musician Rayna Yun Chou for 10 days, which is installed and exhibited in the public space of Boston Chinatown and Harvard Plaza in Cambridge.
①本项目参加的国际竞赛主题为消除孤独（Eliminate Loneliness）。使用“消除”一词反映了孤独被看作一种病症和负面问题对待。本项目的参赛标题为“从消除到升华”（from Eliminating to Elevating），意图是推翻对孤独的负面理解，提出一种新的思考方式。
②普遍认为孤独感在日本美学与哲学思想中占有重要地位，在“侘寂”“物哀”等概念中均有体现。
③活动由波士顿名家系列（Celebrity Series of Boston）与音乐家周韵（Rayna Yun Chou）发起，活动期10天，分别在波士顿中国城以及坎布里奇的哈佛广场公共空间上展出。
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