21st SAG Workshop

on 29 November 2023 Hybrid event

In presence in Gauting and online as webinar.


Trees in Climate Change

Current research results on the influence of the climate catastrophy on the condition, development and likelihood of failure of urban trees.

Program (time CET = UTC + 1/Berlin, order of presentations open)


Short welcome and introduction


Lecture 1, 45 minutes and 15 minutes discussion

Prof. Dr. Thomas Rötzer, TU Munich Weihenstephan, Freising

Ecosystem services of urban trees and the impact of climate change


Lecture 2, 45 minutes and 15 minutes discussion

Dr. Gitta Langer, Northwest German Forest Research Institute, Göttingen

Changes in the interaction of fungi (and other microorganisms) and trees with regard to the consequences of climate change


Coffee break 30 minutes


Lecture 3, 45 minutes and 15 minutes discussion

Prof. Dr. Dirk Schindler, Albert-Ludwigs-University Freiburg

Prediction and modelling of strong wind and heavy rain events in the age of climate change – what is already known and what remains unpredictable?


Lecture 4, 45 minutes and 15 minutes discussion

Prof. Dr. Francesco Ferrini, University of Florence

Challenges for the management and risk assessments of urban trees under changing climatic conditions


Final discussion


End of the event




Wednesday, 29.11.2023, 13:00 to 18:00 h


Institute für Jugendarbeit, Germeringer Str. 30, D-82131 Gauting
Online via Zoom, access options to be communicate


SAG-members free of charge

Non-members 100,- € (without VAT) per person

Students 35,- € (without VAT) per person



20. SAG Workshop – root detection

After the lively discussion about root detection in the SAG WhatsApp group, we would like to invite you to a workshop on the topic.


Date Thursday, May11th, 2023, 09:00 a.m. to 05:00 p.m. CEST
Where Landessportbund Hessen e.V.

Otto-Fleck-Schneise 4

60528 Frankfurt / Germany

Registration please sent an e-mail to
Fee Free for members, non-members: 220,- Euro
For all those who would like to become a member of the SAG: The participation fee will be credited to the annual membership fee if the membership in the SAG starts in the same year.
Language English
Accommodation Guest rooms are available at the conference house. For reservations please contact the Landessportbund directly: Phone +49 69 6789-292 or +49 69 6789-272, e-mail: , https://www.landessportbund-hessen.de/geschaeftsfelder/bildungsstaetten/frankfurt/

Within walking distance there is also the Lindner Hotel Sports Academy https://www.lindner.de/frankfurt-hotel-sports-academy/ankommen.html




09:00 a.m. opening
09.15 a.m. Demonstration of the root detection outside with the system Georadar – Jonas Heck
09.45 a.m. Demonstration of the root detection with the system TreeRadar – Michiel Mol
10:15 a.m. coffee break
10:30 a.m. Lecture “TreeRadar – how it works”, presentation of the detected results on the test tree, Michiel Mol
11:30 a.m. Lecture “Georadar – how it works”, presentation of the detected results on the test tree, Jonas Heck
12:30 a.m. lunch
01:30 p.m. Presentation of practical applications and how it is used in the preparation of reports, Dominique De Baere
02:30 p.m. Exposure of the root and comparison of the results

Final discussion

05:00 p.m. closing


We look forward to seeing you. The board

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: https://www.sag-baumstatik.org/wp-content/uploads/220705-Programme-of-the-lecture-day_Thursday.pdf )

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

1 2