SAG tree statics summer lecture day in Trieste, Italy. 21st of July 2022

In the course of the SAG Summer School 2022 in Trieste, a public conference will take place on Thursday, 21st of July 2022. There, lectures on some topics of the Summer School will be held. SAG members and the well-known experts invited to the Summer School will present important results of their research and practical work to a greater international public.

The full program: (PDF-Version: )

Language of the conference: English – Italian (simultaneous translation from English) Admission: € 100,- per person

Venue: MIB Trieste School of Management Largo Caduti di Nassiriya 1, Trieste

08:30 opening

SECTION 1: Research
09.00 – 9.15 welcome, introduction
09.15 – 10.00 Prof. Dr. Francesco Ferrini, University of Florence: Urban forestry
10.00 – 10.45 Prof. Dr. Steffen Rust, HAWK Göttingen, Germany: Recent results from research on the pulling test method
10.45 – 11.00 Questions & Answers
11.00 – 11.30 Coffee break and networking
11.30 – 12.15 Prof. Dr. Karl Niklas, Cornell University: What we still do not know about Tree Biomechanics
12.15 – 12.30 Questions & Answers
12.30 – 14.00 Break – Lunchtime

SECTION 2: Applications
14.00 – 14.30 Philip van Wassenaer, consultant at Urban Forest Innovations, member of SAG: Tomography on Redwoods in the Western USA
14.30 – 15.00 Andreas Wüstenhagen, board member of SAG Baumstatik & consultant: Supporting habitat trees with Carbon exoskeletons
15.00 – 15.30 Andreas Detter, Chairman of SAG Baumstatik, consultant at TreeConsult, Brudi and Partner: Lessons learnt from pulling tests for visual tree assessment
15.30 – 16.00 Coffee break and networking
16.00 – 16.30 Case studies from SAG members (names to be confirmed)
16.30 – 17.00 Paul Muir, consultant at Treework Environmental Practice, UK, member of SAG: The new SAG Pulling Test Standards
17.00 – 17.30 Questions & Answers, closure and goodbye

Registration possible only via email at

SAG summer school in Trieste, Italy. July 2022

From July 17th to 22nd, SAG is holding a workshop on the subject of pulling tests.
Experts and users want to gather and expand their experiences in small groups in an idyllic environment and also discuss them critically, e.g. new results from science and research on the subjects

– Tree morphology
– case studies of pulling special trees
– Material properties of different trees
– Wind and tree interaction
– and much more.

During the week renowned scientists will join us, such as Karl Niklas, Steffen Rust, Francesco Ferrini and many others in an informal and friendly atmosphere.

19th SAG Workshop

on March 18th 2021 online as a webinar



Wind and Tree Interaction

Current studies and models for the dynamic response of trees in natural winds


Program and speakers (all times CET/MEZ = UTC + 1/Berlin)


8:30     Introduction


8:45     Damien Sellier
Tree sway frequency and damping – finite element modelling and age effects

Damien Sellier is computational modeller at Scion – the New Zealand Forest Research Institute – in Rotorua. His research focuses on developing physics-based models to study tree physiology, wood formation and wood mechanics. He is particularly interested in digital models capturing the real-life complexity of tree organisms. He has a PhD in mechanical engineering; his thesis was the numerical analysis of tree aerodynamic behaviour under wind turbulence in a forest canopy.


9:15     discussion

9:45     coffee break


10:15    Daniel Burcham
Changes in the dynamic properties of trees in natural winds after pruning

Daniel Burcham is the Deputy Director for Urban Trees at the National Parks Board in Singapore. In his research he is studying the behaviour of trees in natural winds.


11:00    discussion

11:30    coffee break


12:00    Toby Jackson
The motion of trees in the wind. A data synthesis

Toby Jackson is currently a postdoc in Cambridge supervised by Prof David Coomes. He is working on the effects of wind on tropical forests. This 4 year NERC funded project uses LiDAR to map forest structure and so model wind flow over a complex forest landscape. He will also be measuring wind speeds and the bending response of tall trees in situ.


12:30    discussion

1:00     lunch break


2:00     Ebba Dellwik
The SingleTree Experiment: An experimental characterization of the wind-tree interaction of an open-grown oak tree

Ebba Dellwik is senior researcher in the Meteorology and Remote Sensing Section in the Wind Energy Department of the Technical University of Denmark. Ebba leads DTU’s research on forest and tree aerodynamics and the study of their impact on the wind conditions. Her focus is on both full-scale and wind tunnel experimental studies with a scope of improving the parameterization of trees in weather and flow models.


2:30     Nikolas Angelou
Mean drag estimation on a full-scale tree using tree-mounted sensors and scanning wind LiDAR measurements

Nikolas Angelou is a postdoctoral researcher in the Meteorology and Remote Sensing Section in the Wind Energy Department of the Technical University of Denmark. His scientific interest is on the investigation of the wind conditions in the atmospheric boundary layer, experimental flow studies using scanning wind LiDAR, wind-tree interactions and in general flow characterization for wind engineering applications.


3:00     discussion

3:30     afternoon coffee break


4:00     Dirk Schindler
Modelling tree responses to turbulent wind from in-situ measurements

Dirk Schindler is the professor for environmental meteorology at the university of Freiburg. From in-situ measurements on trees he derives new models to describe wind and tree interaction.


4:30     discussion

5:00     closing remarks, goodbye


language              English, German (simultaneous translation provided)

time                     Thursday, 18.03.2021, 8:30 am to 5:00 pm

location                online, platform to be announced


fees SAG-members free of charge
non-members 125.- € plus VAT
students 35.- € plus VAT



18th SAG workshop

For September, we actually planned our 18th SAG workshop in Utrecht, the Netherlands. Due to the general situation caused by the corona pandemic, we unfortunately have to postpone the event to indefinite. We are trying to find an alternative date in 2021.

17th SAG Workshop

17th SAG Workshop

on Monday, November 11th 2019 in Frankfurt a.M.



SAG Standards for the Pulling Test Method

– continuing on developing technical standards for pulling tests and their evaluation

This time we would like to continue working on the SAG standard based on our experience and previous workshops. In the second workshop on this topic, the results of the individual working groups will be presented, discussed and further developed. The day will start with the presentations of the working groups. In addition we would like to offer room for any further topics that are not yet part of the standards. Afterwards we will discuss in small groups as well as in the plenary before we are going to coordinate the further work.


language English, translations to German possible
time Monday, 11.11.2019, 9:00 am to 5:00 p.m.
location Landessportbund Hesse e.V., Sportschule und Bildungsstätte
Otto-Fleck-Schneise 4, 60528 Frankfurt
fee lunch (9,50 Euro)
rooms at the meeting place, 64 Euro per single room incl. breakfast
registration with the attached form via mail to registration for members only,
registrations only until Sunday, October 20th 2019


We are looking forward to meeting you in Frankfurt.

The board




Monday, 11.11.2019

8:30 am          opening, registration

8:55 am          welcome, introduction

9:00 am          presentations of the individual working groups (N.N.)

10:30 am       coffee break

11.00 am       discussion of the SAG-standards


12:30 am       joint lunch


1:30 pm          discussion of the SAG-standards, in groups

3:00 pm          coffee break

3:30 pm          discussion, revision, round up

5:00 pm          end of workshop

16th SAG Workshop

16th SAG Workshop

on Monday, 3rd and Tuesday, 4th of June 2019
in Gauting

SAG Standards for the Pulling Test Method
– developing technical standards for pulling tests and their evaluation

This time, we want to exclusively focus on what we have already learned from our experience and previous workshops. We would like to use this information together with the work already done so far to get the SAG standards really a big step ahead. Therefore, we would like to use this workshop to put together the frame of the SAG standard and finish the workshop with a draft version of it.
The plan is to work in the full group on Monday and start with presentations on specific topics like safety during pulling tests, generating usable data during the test, evaluating the data and the minimum level of knowledge to be gained in training before starting with pulling tests. Additionally, we would like to see the ethics discussion be continued that has been started in 2010 in Aschaffenburg and become part of the standards.
In the morning of June 4th 2019 the results of the first SAG funded wind tunnel study on the effect of adjacent trees on the wind load will be presented and their application to the evaluation will be discussed. Then we will continue in working groups and have the Annual General Meeting of SAG Baumstatik in the afternoon at 2 pm.

language English, translations to German possible
time Monday, 03.06.2018, 9:00 am to 5:00 pm
Tuesday, 04.06.2019, 9:00 am to 12:30 am
location Institut für Jugendarbeit, Germeringer Straße 30, D-82132 Gauting
fee lunch paid individually
rooms see attached list
registration – registration for members only


registrations only until Sunday May 19th 2019
We are looking forward to meeting you in Gauting.

The board


Please note:
On Tuesday, 4th of June 2019, the Annual General Meeting of SAG Baumstatik e.V. will take place in the same venue at 2 pm. Please register for this meeting if you like.



Monday, 3.6.2019

8:30 am opening, registration
8:55 am welcome, introduction
9:00 am presentations of previous results of working groups (N.N.)
10:30 am coffee break
11.00 am discussion of the standards
12:30 am joint lunch
2:00 pm discussion of the standards, in groups
3:30 pm coffee break
4:00 pm discussion, revision, round up
5:00 pm end of workshop
In the evening joint dinner

Tuesday, 4.6.2019


8:30 am presentation of results of the wind tunnel study (A. Detter)
9:15 am discussion of the standards
10:00 am coffee break
10:30 am discussion continued
12:00 am summary, outlook, milestones of future work
12:30 am joint lunch
2:00 pm Annual General Meeting of SAG Baumstatik e.V.
5:00 pm end


15 th SAG Workshop

on Tuesday, 25 th of September 2018 in Bremen


Pulling tests on leaning trees

– implications and problems with pulling tests and their evaluations –

This workshop will focus on the joint measuring of leaning trees with pulling tests. We intend to test 5 trees in different directions, analyze data and discuss the evaluation.

Caution: the preparations for the workshop will start on Monday 24.9.2018 at 5:00 pm after the AGM of SAG Baumstatik e.V.

language German and English, translations possible
time introduction/preparations: Monday, 24.09.2018, 5:00 – 6:30 pm
Workshop: Tuesday 25.9.2018, 8:30 am to 5:00 pm
location Schweizerhaus in the Bürgerpark, Bremen, Germany
fee SAG-members lunch paid individually
non-members 225,- € plus VAT
rooms – B&B Hotel Bremen-Hbf, Findorffstraße 28-32, 28215 Bremen
Tel. +49 (0)421 / 619580, E-Mail:
– prizeotel Bremen-City, Theodor-Heuss-Allee 12, 28215 Bremen
Tel. +49 (0)421 / 59 49 94 01, E-Mail:
registration until 10. September 2018


We are looking forward to meeting you in Bremen.

The board


Please note:
On the previous day, Monday, 24 th of September 2018, the Annual General Meeting of SAG Baumstatik e.V. will take place in the same venue. Please register for this meeting if you like. The meeting will start at 2 pm and end at 5 pm.



Monday, 24.9.2018

5:00 pm preparation, presentation protocol for measurements, group formation
In Schweizer Haus, Bürgerpark Bremen (participation not mandatory)
7:00 pm joint dinner in the restaurant La Rucola
Neukirchstraße 1, 28215 Bremen (table reserved for SAG)


Tuesday, 25.9.2018

8:30 am meeting in the Bürgerpark Bremen, Schweizer Haus
Measurements on trees in the Bürgerpark in 5 groups
12:30 am joint lunch
2:00 pm presentations by B. Heilmann, A. Detter
3:30 pm coffee break
4:00 pm discussion and analysis of data
5:00 pm end of workshop


how to get there:

14th SAG Workshop

The 14th Workshop of SAG Baumstatik has take place on 26th of February 2018. In Gauting, almost 40 participants met from 10 countries, from Canada to Croatia, from Britain to Italy.

The focus was on recent findings from research in tree statics at unviversities. Presentations were held with the follwoing contents:

  • Winching tests on Poplar trees on water saturated soils (J. Böttcher)
  • Winching tests on the stability of dead Spruce trees (R. Schröder)
  • Winching tests on the stability of forest Spruce trees (O. Krišāns, Riga)
  • The influence of the geometry on tomography (Prof. S. Rust)
  • Using infra-red markers for optical monitoring of pulling tests (K. Wiegmann)
  • Spectral and wavelet analysis of tilt measurements in natural winds (L. Hoffmann)
  • Correlating pulling tests and tilt measurements in natural winds to calibrate wind load assessments (D. Esche, P. Schuhmacher)

The results will be available in a summarized format shortly on this website. We would like to thank everybody for sharing their results and the fruitful discussions.

The participants of the 14th SAG WorkshopWorkshop



Invitation to the annual

General Meeting (GM)

of SAG Baumstatik e.V.
in Ferrara, Italy,10.10.2017

Dear colleagues,

We would like to invite all members to the annual general meeting in 2017.

Venue: Ferrara, Italy (further informations will follow)

The day before the meeting, we will run the 13th SAG workshop at the same venue.

We have provided the following agenda

9:00 am – 10:30 am
1. Organizational issues of the association
1.1 Report of the Board (activities since the last GM)
1.2 Treasurer’s Report
1.3 New workshops planned in 2018 and 2019
1.4 New election of the board
There are in the moment 5 candidates for the four places in the board:
Michael Schlag, Andreas Detter, Klaus Schöpe, Stefania Gasperini, Michiel Mol.
More candidatures are possible.
The votes procedure will be presented on the GM

10:30 am – 11:00 am coffee break

11:00 am – 12:30 am
2. Memberships
2.1 Members and former members
2.2 Applications for membership

3. Reports from work groups
3.1 discussion and voting on potential research projects etc
3.2 Presentation of a directive for safety during pulling tests etc

4. Completion
4.1 Next Meeting
4.2 Other

We hope to see all of you.

With best regards on behalf of the Board

Edewecht/Gauting/Köln, 28.06.2017                                     Klaus Schöpe

13th SAG Workshop

on October 9 th 2017 in Ferrara, Italy


Tree Architecture and Morphophysiology

The shape of trees is the dynamic result of the continuous interaction of every individual tree with the context, even physical, that surrounds it. Tree architecture is the discipline that, defining the principles underlying such interaction, allows to reconstruct the past of a tree, to understand its present and to predict its future evolution.

Through tree morphophysiology it is also possible to relate the architecture of a tree with its biological and functional characteristics, defining the morphological and anatomical relationships that connect the different parts of it. In this way it is possible, for example, to infer the root system organization from the characteristics of the tree’s canopy.

Similarly, it is possible to identify any energetic, hormonal or structural alterations, because the tree architecture would show the consequences of them, or you can evaluate the importance of some symptoms, such as cavities, depending on the indi-
vidual evolution of a tree.

Although the principles of tree architecture and morphophysiology have been studied for more than thirty years, their use at diagnostic and application levels is still very limited. The presentation, from a practical point of view, intends to contribute to highlight this subject.

Dr Giovanni Morelli, agronomist and arborist, owner of Progetto Verde since 1994, is a consultant in in urban arboriculture, specialized in tree risk and tree stability assessment. He has written numerous articles and he is a lecturer in university courses. He has been speaker at more than 60 national and international conferences or seminars. He is a member of the ISA International Society of Arboriculture (ISA), of the SIA (Società Italiana di Arboricoltura), and of SAG Baumstatik e.V.. He is ISA Certified Arborist, ETT – European Tree Technician, Board Certified Master Arborist (ISA) and TRAQ (Tree Risk Assessment Qualification).

The presentation will be held in English language. Translations of questions from English to German or Italian will available upon request.


8:30 – 8:45 Opening, registration
8:45 – 9:00 Welcome, introduction
9:00 – 10:20 Giovanni Morelli: Tree Architecture
10:20 – 10:40 Coffée break
10:40 – 12:15 Giovanni Morelli: Tree Morphophysiology
12:15 – 12:45 Question time
12:45 – 13:30 Lunch break
13:45 – 15:45 Observation of tree architecture in Massari Park
16:00 – 16:30 General discussion, end


On the following day, October 10 th , the Annual General Meeting of SAG Baumstatik will take place in the same venue. The AGM is not open to the public.

language: Italian, English
time: Monday, 9.10.2016, 9:00 am to 4:30 pm
location: Sala Imbarcadero 2 – Castello Estense – Piazza Castello – Ferrara
fees: SAG-members 35.- € for food & beverages
non-members 245.- € plus VAT
early bird 180.- € plus VAT registration before Sept. 9 th
rooms: Hotel Europa, Corso della Giovecca, 49, 44121 Ferrara,
we reserved 20 rooms for SAG workshop participants until the 8 th of September with special prices,
registration: or phone +49-89-752150

12th SAG Workshop

on October 4 th 2016 in Nancy, France


Advances in biomechanics and mechanobiology for the diagnostic of urban trees

Over the last 3 decades, the biomechanical inputs for the analysis of urban trees have been largely developed, starting with the seminal works of Lothar Wessolly and Klaus Mattheck. As a consequence, leading experts in the diagnostic of mechanical stability and safety of urban trees are now using techniques of biomechanical engineering such as model of static wind loads on trees and/or static tension-flexion tests.

We would like to make an update and to share ideas with arboriculture experts about novel findings from the biomechanics and mechanobiology research along 3 lines directly related to tree safety: crown reconfiguration in wind, dynamics and compartmentalization of mechanical energy, long term acclimation of trees (see program).

The following exchange between scientists and expert will be on i) how to improve current biomechanical tools for the mechanical analysis of trees and ii) how we may change from punctual diagnosis to longitudinal monitoring and long-term diagnosis.

language English, translations to and from French and German on request
time Tuesday, 4.10.2016, 8:30 am to 5:30 pm
location INRA Centre de Nancy, Rue d’Amance,
54280 Champenoux, France
building and room number to be announced
fees SAG-members only for food and drinks
non-members 245.- € plus VAT
rooms QuickPalace
midway between Nancy and INRA,Ibis

Stanislav in Nancy

regristration Öffnet ein Fenster zum Versenden der E-Maila.akontz(at)
or phone +49-89-752150


Download the Invitation with detailed PDF-Program.

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